Updated: Aug 12, 2022
The Bible has much to say about sound doctrine, which is referred to by other translated words, such as: “truth” (1 Tim. 2:4), “the faith” (1 Tim. 3:9; 2 Tim. 3:8; Ti. 1:13; Ju 1:3), “wholesome words” (1 Tim. 6:3), and “sound words” (2 Tim. 1:13). Doctrine and its companion terms are referred to 59 times in 1 and 2 Timothy alone. The two Greek words translated “doctrine” (“didaskalia” and “didache”), are also translated “teacheth” (Rom. 12:7) and “learning” (Rom. 15:4). These Greek words are used more than 140 times in the NT, which shows how important doctrine is before God.
"All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness:" (2 Tim 3:16)
The first reason that God gave us His inspired Word was for doctrine. For teaching. So we can know God and we can know how to be saved and live for Him, and we can also know the history of the world from the antiquity of the sun, among many other things.
Everything hinges upon sound doctrine because sound doctrine is simply the truth of God's Word. Consider some of these:
We can only be saved through believing the right doctrine (Rom. 6:17; 1 Jn. 5:20; 2 Jn. 1:9). Without the Word of God we cannot be saved (Rom. 10:17; 1 Pet. 1:23); which reflects the utmost importance of sound doctrine (2 Tim. 1:13; Ti. 1:9-13; 2:1), the proper interpretation and teaching of Scripture.
We can only know the Triune God through sound doctrine. "Jesus answered them, and said, My doctrine is not mine, but his that sent me. If any man will do his will, he shall know of the doctrine, whether it be of God, or whether I speak of myself." (Jn. 7:16-17). God's will and sound doctrine are intricately linked, as we see here. To know anything about the Triune God and His will, the doctrine has to be sound and then practiced soundly.
We can only worship God the Father in "spirit and in truth" (Jn. 4:23), and truth is sound doctrine. "God is a Spirit: and they that worship him must worship him in spirit and in truth." (Jn. 4:24). It is through the quickened spirit and sound doctrine that we worship God. Sin or worldliness or doctrinal error will "quench" and "grieve" the Holy Spirit (1 Th. 5:18; Eph. 4:30) and in His love, God will chastise His children (Heb. 12:5-11) "that [they] might be partakers of his holiness" (v. 10). Sound doctrine is required for both salvation and walking in obedience, and that is necessary to worship God.
We can only grow in the grace and knowledge and wisdom of God through sound doctrine. Obedience to God's Word requires believing God's Word. Believing God's Word requires believing the doctrine (teachings) found in God's Word. Believing the doctrine found in God's Word, means believing the doctrine properly, rightfully, soundly. Unsound doctrine will affect this entire cascade of growth and result in people “tossed to and fro, and carried about with every wind of doctrine, by the sleight of men, and cunning craftiness, whereby they lie in wait to deceive” (Eph 4:14), “carried about by strange and diverse doctrines” (Heb 13:9). If we believe something wrongfully, we will also naturally obey this unscriptural belief, which means disobedience to sound doctrine. Consider a case in point: if one was to believe that soul-winning was left merely up to the clergy, then one would have to disobey the sound doctrine of the Great Commission as found in such places as Mk. 16:15-16 and Matt. 28:18-20 and Lk. 24:44-48, etc. Furthermore, it would cause unsound doctrine and disobedience in other areas such as 2 Cor. 5:17-6:2, where believers are commanded to be ministers of reconciliation and ministers of the Word and ambassadors of Christ and workers together with God. Thus we see a cascade of effect, just by simply have one unsound doctrine. "A little leaven leaveneth the whole lump." (Gal. 5:9; I Cor. 5:6). We are commanded to continue in the sound doctrine of the Apostles (Ac. 2:42; I Jn. 1:3). The Apostles’ greatest joy was to see Christians walking in the truth (2 Jn. 1:4; 3 Jn. 1:3-4), and we can be assured it is Gods greatest joy to. How can we walk in the truth if we do not believe or know or follow sound doctrine (truth)?
We can only exhort and convince (Ti. 1:9), rebuke and reprove (2 Tim. 4:2), correct and instruct (2 Tim. 3:16) our brethren through sound doctrine (2 Tim. 3:16). And we do this so that "the man of God may be perfect, throughly furnished unto all good works." (2 Tim. 3:17). Those not sound in doctrine we are to “rebuke them sharply, that they may be sound in the faith" (Ti. 1:13) and that rebuke comes by sound doctrine. Sound doctrine is “iron” and “Iron sharpeneth iron; so a man sharpeneth the countenance of his friend” (Pr 27:17). Without sound doctrine, you won’t be “iron” so you won’t be sharpening anybody.
We can only be sanctified through sound doctrine. Jesus praying to the Father said "Sanctify them through thy truth: thy word is truth." (Jn. 17:17). A few passages later, Jesus said that He, for our sakes, sanctified Himself, that we "also might be sanctified through the truth." (Jn. 17:19). If the truth is altered in any way, which then becomes unsound doctrine, we cannot be properly sanctified. Our past sanctification, which occurred at salvation, and our future sanctification, which will occur at the resurrection, would not be effected, but our present sanctification surely would, and this will effect us being conformed to the image of Christ.
We can only show true godly love, when we are grounded in the truth (2 Jn. 1:1-2; 3 Jn. 1:1), which is sound Bible doctrine. For example, 1 Cor. 13, the chapter on love, which is the love of God (agape love), we note that godly love can only be shown when grounded in the truth (vv. 1-6). “Love … rejoiceth in the truth” (1 Cor 13:6).
We can only contend and fight for the faith, and discern false doctrine by knowing and understanding sound doctrine. The Bible warns us to be careful of winds of false doctrine (Eph. 4:14). It was only a "minor" twisting of God's truth, that led to Eve believing Satan's lie (Gen. 3:1-3). The Devil always works in very subtle and gradual ways; hence the importance of fighting for the sound doctrine of God's Word, regardless how minuscule and minor it might appear. Contending is not unloving but rather quote the contrary; a demonstration of great love for the truth of God's Word, the very Word that He has magnified above all His name (Ps. 138:2). Believers are exhorted to "earnestly contend for the faith which was once delivered unto the saints." (Ju. 1:3); and this is following the example of the apostles (e.g. Ac. 13:9-12; 15:1-2; 1 & 2 Tim). "The faith" can only consist of sound doctrine and for that we are to earnestly contend for, which means to strive for; to fight for; to struggle for. What part of the faith are we to defend against error? All of it. There are no "non-essentials" in Scripture, nor are there doctrines not important enough to defend. Paul praised churches for keeping all of the apostolic tradition, even such seeming unimportant things such as the teaching on hair (1 Cor. 7) and how to keep the Lord’s Supper (1 Cor. 11:2). No false doctrine is to be allowed (1 Tim. 1:3). We are to contend “earnestly” which means, zealously; importunately; and eagerly. "Hold fast the form of sound words, which thou hast heard of me, in faith and love which is in Christ Jesus." (2 Tim. 1:13). "Holding fast the faithful word as he hath been taught, that he may be able by sound doctrine both to exhort and to convince the gainsayers. For there are many unruly and vain talkers and deceivers, Wherefore rebuke them sharply, that they may be sound in the faith; Not giving heed to Jewish fables, and commandments of men, that turn from the truth." (Ti. 1:9-10,13-14). We are not to give heed to any turning from the truth (unsound doctrine). Every preacher and teacher of Gods Word is instructed to "But speak thou the things which become sound doctrine:" (Ti. 2:1).
We can only be adorned with godly living through sound doctrine (1 Tim. 6:1,3; Ti. 2:1-8). The Bible has commanded believers to be doctrinally uncorrupt, to have doctrinal gravity, doctrinal sincerity, and doctrinally sound speech (Ti. 2:7-8). The preachers of all people are commanded to teach only “sound doctrine:" (Ti. 2:1) and “no other doctrine” (1 Tim 1:3).
We can only fellowship through sound doctrine, if you are about fellowshipping in truth and obedience to God’s Word. Fellowship is firstly and most importantly based upon doctrine (1 Tim. 6:3-5). "That which we have seen and heard declare we unto you, that ye also may have fellowship with us: and truly our fellowship is with the Father, and with his Son Jesus Christ." (1 Jn. 1:3; see also I Tim. 6:3-5; II Tim. 4:1-4). It was apostolic doctrine that the apostles "seen" and "heard" and was told them by the Holy Ghost (2 Pet. 1:21) and had declared unto believers, and it was this doctrine that decided fellowship between the believer and the apostle ("that ye also may have fellowship with us"). Furthermore, it is sound doctrine that brings us into fellowship with the Father and His Son (I Jn. 1:1-9). We are not to fellowship with those who teach and promote false doctrine but rather are to avoid (separate from) them and even mark (expose) them (Rom. 16:17). Those who will not teach and consent to the wholesome words of Christ are to be separated from (1 Tim. 6:3-5). Those who abide not in the doctrine of Jesus Christ are not of God and are not be to received (2 Jn. 1:9-10). From a human perspective, being in close fellowship with another professing Christian who willfully believes and follows something that is doctrinally incorrect, even a doctrine that might have perhaps no actual bearing on our salvation, might seem right and even noble if its for the purpose of helping them; however, from a Biblical perspective it is seen as disobedience and will effect fellowship with the Father and His Son (2 Cor. 6:16-7:1; 1 Jn. 1:1-6; 1 Tim. 6:3-5). Choices in our doctrinal beliefs always has consequences, just like sin or worldliness or anything else for that matter. When unsound doctrine is entertained, fellowship is broken. Unsound doctrine must be rebuked and reproved and if their is a genuine repentance and turning from it unto the truth, then fellowship is restored (2 Tim. 2:24-25). Paul exposed men for all the world to read since the canonization of Scripture, for simply teaching that the resurrection is past already. This doctrine might not even effect salvation; how much the more should heretics be exposed for teaching anything contrary to Gods Word concerning salvation (i.e. Baptismal regeneration, losing salvation, no repentance, Christ's blood not necessary for redemption, etc) or concerning the doctrine of Jesus Christ (2 Jn 1:9-11) or God or the Triune God, and any other fundamental truth that will effect the soul of man for all eternity. The truth is, all doctrine is important, although some is more important, and all unsound doctrine must be sharply rebuked and separated from
Preachers are only to teach "sound doctrine" (Ti 2:1) and no "other doctrine" (1 Tim 1:3). No exceptions. Clearly it matters to God what we believe concerning Bible doctrine and clearly it matters as to how it will effect us coming to salvation and living the Christian life.