Practice is from position, but never to position. The ethical mandates of the New Testament are decisively clear that believers are to walk in the richness of the position we have been given (Eph1:3), and that the position is actually necessary for the walk (Heb 11:6). Never is a believer warned that his or her position as a child of God is in danger because of their walk.
Certainly there are warning passages. Hebrews 4:1 warns us to fear lest we “may seem to have come short” of entering His rest. Hebrews 4:11 prescribes diligence so that “no one will fall.” In the same context, the writer exhorts, “let us draw near with confidence to the throne of grace, so that we may receive mercy and find grace to help in time of need” (4:16). [Why else would we need continuing grace and mercy if we were without sin in our practice?] Later, the writer reminds, “we are not of those who shrink back to destruction (Heb 10:39). There is no future of destruction for believers because “the believing one has eternal life” (Jn 6:47). Once eternal life is given, then by definition, it is eternal. Any end to it would make it something other than eternal.
The warnings, then, are not about loss of position, but about loss within that position. One whose practice is lacking will suffer loss – even losing reward – but that person is still secure in position (1 Cor 3:12-15).
The Corinthians illustrate well how position should lead to a certain kind of walk but doesn’t always. Paul chastises them for being fleshly (1 Cor 3:1), as they engaged in severe immorality (1 Cor 5:1). He challenges them to stop behaving immaturely like those who have not been transferred to the kingdom of God (1 Cor 6:9-10; Col 1:13), and instead to have maturity in their thinking (1 Cor 14:20). Some of the Corinthians were exceedingly guilty in their practice, but all of them had been washed, sanctified, and justified (1 Cor 6:11).
Another key evidence for the positional security of the believer is the work of the Holy Spirit. The Holy Spirit enables believers to walk well, and He indwells every believer as the guarantee of eternal life (Eph 1:13-14). He baptized every believer into the body of Christ (1 Cor 12:13). Every believer has Him (Rom 8:9), and He is the source of fruitbearing in the lives of all believers (Gal 5:22). Certainly, one’s deeds can provide an evidence of position, but even when our deeds seem to be contrary, the witness of the Holy Spirit remains true (1 Jn 4:13). Our source of assurance is not our deeds, but the Holy Spirit Who lives within us.
Further, notice how the Biblical writers motivate based on position:
Therefore I urge you, brethren, by the mercies of God, to present your bodies a living and holy sacrifice, acceptable to God, which is your spiritual service of worship (Rom 12:1).
Therefore I, the prisoner of the Lord, implore you to walk in a manner worthy of the calling with which you have been called…(Eph 4:1).
Therefore leaving the elementary teaching about the Christ, let us press on to maturity, not laying again a foundation of repentance from dead works and of faith toward God…(Heb 6:1).
Are you so foolish? Having begun by the Spirit, are you now being perfected by the flesh (Gal 3:3)?
Therefore the Law has become our tutor to lead us to Christ, so that we may be justified by faith. But now that faith has come, we are no longer under a tutor (Gal 3:24-25).
Therefore if you have been raised up with Christ, keep seeking the things above, where Christ is, seated at the right hand of God. Set your mind on the things above, not on the things that are on earth. For you have died and your life is hidden with Christ in God. When Christ, who is our life, is revealed, then you also will be revealed with Him in glory. Therefore consider the members of your earthly body as dead to immorality, impurity, passion, evil desire, and greed, which amounts to idolatry. (Col 3:1-5).
Blessed be the God and Father of our Lord Jesus Christ, who according to His great mercy has caused us to be born again to a living hope through the resurrection of Jesus Christ from the dead, to obtain an inheritance which is imperishable and undefiled and will not fade away, reserved in heaven for you, who are protected by the power of God through faith for a salvation ready to be revealed in the last time (1 Pet 1:3-5).
Christian (i.e., Biblical) ethics are based not on fear of losing one’s position as a child of God or as a member of the body of Christ. Instead, one’s position is the platform from which they should practice. It is the joyous new beginning from which we can honor God, having been redeemed and cleansed.
Sadly, it is not uncommon for us as believers to sin against God – even in some horrific ways. In this we must know that we should not continue in sin so that grace can increase (Rom 6:1-2). We are told straightforwardly that we are not to let sin rule over our bodies (Rom 6:12, 14), and that grace is not a license to sin (Rom 6:15). In fact, Paul explains that for a person who has died to sin – as all believers have – to continue in sin is an utterly ridiculous proposition (Rom 6:2). It is nonsense, but still possible. Instead, we should consider God’s mercies and present our bodies to Him – that is reasonable (Rom 12:1).