Based on Greg Bahnsen’s “By This Standard,” (1991).
- Will the Holy Spirit replace the law of God?
We must observe in this regard that the Holy Spirit does not replace the law of God in the Christian life, nor does He oppose the law of God in our behaviour. The gracious Spirit who empowers our sanctification does not speak for Himself, giving a new pattern for Christian behaviour (Jn.16:13). Rather, He witnesses to the word of the Son (Jn.14:23-26; 15:26; 16:14). The Spirit is not an independent source of direction or guidance in the Christian life, for His ministry is carried out in conjunction with the already given word of God (cf. I Cor.2:12-16).
In terms of our sanctification this means that the Spirit enables us to understand and obey the objective standards of God’s revealed law. It does not mean that Christians who are indwelt by the Spirit become a law unto themselves, spinning out from within themselves the standards by which they live. What the Spirit does is to supply what was lacking in the law itself-the power to enforce compliance. “What the law could not do, weak as it was through the flesh, God did: sending His own Son in the likeness of sinful flesh and as an offering for sin, he condemned sin in the flesh in order that the requirements of the law might be fulfilled in us, who do not walk according to the flesh, but according to the Spirit” (Ro.8:3-4) (p.69).
- What is the believer’s behavioural blueprint?
God’s law is still the blueprint for sanctified behaviour. This is completely unaffected by the Spirit’s ethical ministry in the believer. The Holy Spirit does not oppose that law in the slightest degree but, instead, empowers obedience to it. “I will put my spirit within you and cause you to walk in my statutes, and you will be careful to observe My ordinances” (Ezek.36:27). Whereas the letter of the law brought death to man because he was unable of himself to comply with it, the Spirit of God enlivens men so that they can conform to God’s standards (II Cor.3:6).
Therefore the sure test of whether someone has the Spirit abiding in him or not is found in asking if he keeps the commandments of God (I Jn.3:24). A Biblical view of the work of the Holy Spirit reinforces the validity of God’s law for the Christian, showing how the law (as pattern) and the Spirit (as power) are both indispensable for sanctification (p.70).
- What should motivate us?
Those who are genuine believers in Christ know very well that their salvation cannot be grounded in their own works of the law: “…not by works of righteousness which we did ourselves, but according to his mercy He saved us, …that being justified by His grace we might be made heirs according to the hope of eternal life” (Titus 3:5-7). The believer’s justification before God is grounded instead in the perfect of Jesus Christ (Gal.3:11; Ro.5:19); it is His imputed righteousness that makes us right before the judgement seat of God (II Cor.5:21). “A man is justified by faith without the deeds of the law” (Ro.3:28).
- Does Christian love require God’s law?
Because God has shown His love toward us, we are now to live in love to Him and our neighbour (Eph.5:1-2, I Jn.4:7-12, 16-21). On these two love commandments- toward God and toward our neighbour (as taught in the Old Testament [Deut.6:5; Lev.19:18]) -hang all the law and the prophets, said Jesus (Mat.22:37-40). Indeed, “love is the fulfilling of the law” (Ro.13:10).
But in the thinking of Jesus and the apostles, does this mean that Christians can dispense with the law of God or repudiate its details? Not at all. Moses had taught that loving God means keeping His commandments (Deut.30:16), and as usual, Jesus did not depart from Moses: “If you love Me, you will keep My commandments” (Jn.14:15).
The love which summarises and epitomises Christian ethics is not a vague generality or feeling that tolerates, for instance, everything from adultery to chastity. John wrote: “Hereby we know that we love the children of God, when we love God and do His commandments. For this is the love of God, that we keep His commandments” (I Jn.5:2-3). Love summarises the law of God, but it does not abrogate or replace it. As John Murray once wrote, “the summary does not obliterate or abrogate the expansion of which it is a summary.”
God’s commandments give the specific character and direction to love as exercised by the believer. Rather than being a law unto itself (autonomous), love is a reflection of the character of God (I Jn. 4:8) and must therefore coincide with the dictates of God’s law, for they are the transcript of God’s moral perfection on a creaturely level
God has loved us in that He saved us by grace through faith. Accordingly the Christian life ought to reflect the principles of grace, faith and love; without them it is vain and insignificant. However, far from eliminating the love of God, a gracious ethic of faith and love establishes the permanent validity of, and our need for, the Lord’s commandments (p.76-77).
- What character does God require in His people?
The moral man is one characterised by a holiness which reflects the nature of God, as expressed in His revealed law. The follower of Christ will attempt to emulate the Saviour’s virtues, as corresponding to His revealed law. The genuinely Spiritual man will follow the leading of God’s Spirit, thereby walking in the paths of God’s commandments. What we have seen is that the motivational approach to ethics is not to be divorced from, or set in contrast to, the normative approach to ethics.
Christians will want the grace of God that saved them to be manifest in their actions and attitudes; they will want to live out every moment of life in a faithful and loving way so as to be a witness to what God’s faithful love has done for them. And again, when we look at Scripture to find the implications of a gracious lifestyle which is characterised by faith and love, we learn that God’s law shows us the way (p.80).
 John Murray, “Principles of Conduct,” 1957, p.192.