The only way discernment can be a sustainable practice is to first know what what the Bible teaches. The very meaning of the word discernment (to judge/decide accurately) requires that the standard against which everything is being compared is clearly understood. Knowing the truth only comes by way of a continuous commitment to the prayerful study of Scripture. And knowing what God's Word says is critical, so that one might accurately compare what purports to be biblical to the Bible. DL Moody said, “The best way to show that a stick is crooked is not to argue about it or to spend time denouncing it, but to lay a straight stick alongside it.” There is no shortage of messages that profess to be both Christian and biblical, and yet are neither. Christians must be Bereans who are committed to the sufficiency and authority of God's revelation in Scripture. We must also be ferocious defenders of the Truth, as it has always been under attack by our spiritual enemy. The truest spiritual warfare has always existed in the battlefield of our mind; this is war for Truth. It is no coincidence, then, that the one offensive weapon issued to us in the armor of God is the Sword of the Spirit, which is the Word of God.
The first step to discerning the problem of false teaching is to admit they still exist today. While this might go without saying, most Christians simply are not comfortable saying that someone with a pattern of false teaching is a false teacher. Most are uncomfortable because they think it is judgmental and mean-spirited to call someone a false teacher or heretic. One popular hip-hop artists said, "Today the only heresy is saying that theirs heresy." This is the sad reality of our day. Others are reluctant to call someone a false teacher, because they lack the ability, being biblical illiteracy they feel unworthy of calling anyone out on something they themselves can't say for sure is in error. Either way, the first step is to recognize that there are both deceived and deceptive Bible-twisters who regularly teach unbiblical and historically anti-Christian doctrines. This has been true since the time before Christ, back to Moses and the prophets. And despite widespread naiveté, it is still true today. As you read this, there are men and women actively misleading, deceiving, and damning to hell many people who think they have the truth. Christians must take a biblical tone of concern for God's people in the Church. And pastors must selflessly defend God's Word in the pulpit, refuting those who contradict sound doctrine. There are false teachers and heretics that must be warned of, silenced, exposed, confronted, and avoided.
This was true in the early church and becomes more and more true with time. At the close of each period of biblical revelation (the Hebrew Bible and the teaching of the Apostles), God repeats the warning to not add or remove anything to His Word. This command coupled with the fact that the Bible we have today contains the very books and revelation God intended for His Church means that Christians have a closed cannon of Scripture. This is to say, God has finished telling the Church everything we need to know regarding Himself, salvation, and how we are to live until Christ returns for us. This finally occurred when the mystery of the Gospel of Jesus Christ was revealed to the Apostles. There are no more hidden mysteries to be discovered by the uber-spiritual or the intellectual elite. Though the truth in Scripture is spiritually discerned, the way of salvation and sanctification can be plainly understood. And while the help of a gifted teacher is often necessary, this teaching is not to be confused with some mystical ability to receive and reveal new meanings that the Church has historically overlooked or was not previously able to understand. (similar to #6)
It can be tempting to over-allegorize and to mis-apply the Old Testament in particular. It is critical to keep in mind that this portion of our Bible contains behaviors, promises, and even commands that were uniquely for God's chosen people, Israel, and therefore are to be read and applied to our lives today differently than one might a New Testament epistle (letter to a church). The primary danger here is that we insist on claiming for ourselves today the many circumstantial and material promises God made to His people at various periods of their history, coming out of slavery, warring against idolatrous peoples, or being released from exile. Many have, with the best of intentions, taken excerpts of God's great kindness, mercy, and faithfulness out of its historical, geographical, and national context, appropriating them to the Church today, with whom He has no such covenant. Praise God for His revelation of His relationship to Israel. It is largely symbolic of the more glorious spiritual life in Christ to come. Today, God offers all who believe a better covenant. However, many in the professing Church are not content with the all of the spiritual blessings we have in Christ and would rather claim the more material promise of God for descendants, land, prosperity, blessing, and victory, etc. The stories of God and Israel powerfully display God's holiness, trustworthiness, righteousness, faithfulness, mercy, power, and His judgment.
*Regarding the Law (of Moses): While the Moral Law, given by God thru Moses, transcends the Old and New Covenants, Israel's Civil and Ceremonial Law pertained only to Israel within the context of the theocracy (God-government). The Civil and Ceremonial Law are still extremely rich in value in terms of understanding God as well as the rule of God for society and worship, however they are no longer considered law outside of that context.
Doctrine is critical, but it is not the only thing that matters. Christians must consider the personal lives of all who profess to be in Christ, and most strictly, those who teach. While on one hand, bad doctrine leads to bad living, it is possible for a teacher (at least for a season) to have relatively sound doctrine, yet lack in the corresponding fruit of holiness or love. A teacher's life and teaching must work in tandem, the one constantly commending the other. And while perfection cannot be expected, one must require spiritual leaders to be, by God's grace, exemplary of a life lived for Christ. Sin is a serious danger and our enemy is a threat for spiritual leaders, and they are not beyond temporarily falling into even gross sin. In other cases, a false teacher with largely solid theology may subtly show their falsehood by a pattern of moderate sin, such as the abuse of their Christian liberties, or the occasional sinful slip of the tongue, etc. Christ Himself, speaking of false teachers, warns not only of their false teaching, but also of their bad fruit. Their lives ought to preach as sound a doctrine as do their words. A more subtle, yet telling aspect of a teacher's personal life to watch closely is their partnerships. To share a stage or a television network with dangerous or false teachers is to compromise the clear and complete gospel they, themselves, preach. The people with which a teacher is willing to fellowship and partnerships, is no small thing, and bears implications on their commitment to biblical doctrine.
Not everything a false teacher says is biblically false. But that much is obvious. No one would listen to them if they didn't teach at least a minimum amount of widely accepted biblical truth. In fact, it is possible for a teacher to be largely in line with historical Christianity, and stray in only a few primary areas of biblical doctrine, and still be guilty of gross error. While many Christians will not notice the variance , many more, unaware of the theological implications, too quickly dismiss what is wrong with their teaching in the interest of what that is right with their teaching. We would be wise to understand there are deceivers who intentionally teach just enough spiritual and biblical truth in order to mask their dangerous and blasphemous lies. This kind of deception has historically been for the purposes of money, power, or worse, to damn souls to hell in unbelief. As Paul teaches us, we should not be surprised if "deceitful workmen" sometimes sound so sincere, positive, even godly, as even Satan disguises himself as an angel (messenger) of light. Tragically, many false teachers are sincerely misled and incidently mislead others. However, ignorance to the influence of our evil spiritual enemy is not a virtue and is not helpful. We must not give them the benefit of the doubt simply because they are sincere; too much is at stake.
Christians are under no obligation to believe that anyone's subjective impression is in fact from God. This especially applies when teachers claim to have heard from God, personally and directly. While God, by His Spirit, sovereignly guides and directs Christians, He need no longer speak. The word "speak" is important and is typically used to refer to an experience where someone either claims to have heard an audible voice or to have felt even a (reportedly) undeniable "impression" or "whisper" that you just know was from God. This is very dangerous speech. Even those who admit they did not hear His voice audibly, have to also admit they can't be completely sure that what they felt, sensed, etc. was unquestionably from God. And since, it may not be authoritative, it must necessarily not be authoritative at all. This is the danger of subjective impressions. There is no biblical precedent and certainly no biblical command that would have us listening for God to speak to us outside of His Word. Even when Jesus shows His disciples how to prayer, He says nothing of hearing a response from God. This is because God has already revealed Himself to mankind in His Word and by His Son. In this case, biblical discernment means to compare what people say or write in the name of God, to the sufficient Word of God. Many false teachers claim to offer fresh insight and direction directly from God. However, faithful teachers are content with, even humbled by, the embarrassment of riches we find in God's Word.
It can be tempting to believe that God intended for us to be the hero of the Bible stories. This occurs when a teacher reads themselves or their listener "into the text." This erroneous practice is called "Eisegesis." By exchanging the preposition Ex at the front of the word Exegesis (to take OUT) with Eis, we get the word Eisegesis (to put IN). Eisegesis, then, is the process of "putting into" the text one's own presuppositions, desires, agendas, etc. While this approach to the Bible may appeal more to our interests, particularly those of lost people, the job of the pastor is to preach the Word, to explain its meaning and proclaim our need for it. A faithful teacher will exegete (or pull OUT of text) what God has said in His Word. A fundamental truth about the Bible is it is not about us. It is about God. This is far more than semantics or a word-play. The Bible is to be read correctly, with God as both the author and the subject, and with His Church as the direct object. Likewise, the Bible is to be applied appropriately as we consider to whom it was originally written, then what it meant to them, and lastly what its message and implications are for us today. Scripture is often twisted in this way, by over-playing our role in the story. This is typically done to generate appeal, scratch a felt-need itch, or support a teacher's own agenda. And other times it is done simply out of sincere ignorance and a lack of biblical training (hermeneutics). We will frequently mis-teach and mis-apply God's Holy Word if we insist on finding ourselves, instead of Christ, in every text. While God's Word is written to us, It must be enough that God's Word is written about God. It must also be enough that this book was quite graciously preserved for us in order that we may know Him how to be saved and how we are to live!
Despite how the world thinks, popularity is not an automatic sign of success. A packed out building, multiple services in multiple location, a certified Twitter account, and books on the NY Times bestseller list are far from proof of a blessed teaching ministry. There are a lot of ways even professing Christian teachers can draw a crowd and create a following without being overtly biblical. No doubt, there are sound teachers who the Lord causes to be quite influential while maintaining a strong commitment to God-honoring and biblical teaching. So, while having influence or a ministry that impacts many people is certainly not a bad thing, Christians ought to be extremely careful to automatically validate a teacher on the basis of popularity alone. Far too often, teachers are surrounded by people who simply want there emotional and spiritual itches scratched, and there is no shortage of teachers happy to oblige. Charles Spurgeon is quoted to have said, "That very church which the world likes best is sure to be that which God abhors." Many false teachers are popular because they are appealing to man's desires and felt needs for the purposes of attendance, money, and status. Unfortunately, the more popular such teachers get, the more insulated to biblical criticism they become. Solid teachers take no joy in social rejection except to know Christ too was rejected by most, due to the offense of His message. Biblical discernment would have us value the faithfulness of a given teacher to the Text far more than we would his following.
Regardless of the portion of Scripture, Christ is the ultimate focal point of Scripture. One should expect at least a meaningful reference to, if not an emphasis on, Christ and our subsequent Christ-likeness from every teaching. Sadly, many teachers give themselves and many other social and philosophical topics far more attention than they give Christ. The Old Testament points forward to Him and the spiritual reality of being in Christ. The New Testament points backward to Him and His finished work on earth, His work in heaven as our high priest, and His future return and reign. A faithful teacher gives proper honor to Christ by beginning with a biblical text and customarily following the biblical pattern of expositional (verse-by-verse) teaching. An unfaithful teacher will make either himself, his creative delivery, or his pragmatic application the focus of the message. Since the influence of Pentecostalism, even the Holy Spirit has been given false-honor by way of an over-emphasis on ecstatic speech (tongues) as well as demonic and artificial manifestations of miracles. More recently, the Spirit of God is blasphemed by an emphasis on personal divine revelation knowledge and extra-biblical vision-casting that is supposedly from God the Holy Spirit. It is important for believers to understand the Father's ultimate will to honor the Son and the Holy Spirit's role, likewise, is to represent and honor the Son. It follows, then, that an appropriate teaching of Scripture will necessarily point to Jesus. This is what it means that Jesus as The Word made flesh. To focus on anything that doesn't refer back to or directly emphasize Him is simply to not preach the Word. The faithful teacher will be quite satisfied to repeatedly show us Christ in the text.