The world is an ocean of lawlessness and disobedience to God, and it is a dangerous place in which we are set, commissioned to proclaim the gospel. You have to be so careful with the world, and that is in the background when you come to verse 17 – ‘Sanctify them,’ purify them.
Are the Ten Commandments still in force for believers today? Note that the moral law of God in the Ten Commandments is a reflection of God’s character. That is one reason why it is eternal and why it cannot be seen as something that was just for the Jews. ‘Thou shalt not commit adultery’, tells us about the faithfulness of God. He is eternally faithful to his covenant of grace. ‘Thou shalt not kill’, show us that God is a God of justice. Whilst God most certainly does take life and inflict punishment upon people, he does not do so aside from his perfect justice. ‘Thou shalt not steal’: God is not a spoiler, he is a giver. He is a gracious God, and he gives richly and freely through salvation. There is a lot of false teaching about which says the commandments were for the Old Testament and not for today. But that is not what the Scripture teaches. The commandments are for both Testaments. Describing the people of God in the New Testament, Jeremiah says, ‘After those days, saith the Lord, I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people’ (Jeremiah 31:33), words which are also quoted in Hebrews 10:16. The law is still there in the New Testament and it is the basis of judgement for every soul, says the apostle Paul: ‘Now we know that what things soever the law saith, it saith to them who are under the law: that every mouth may be stopped, and all the world may become guilty before God. Therefore by the deeds of the law there shall be no flesh be justified’ (Romans 3:19). In Romans 13:8-9 he defines love in terms of the Ten Commandments. The law is the under-girding standard of Christian conduct, without any doubt. James agrees with this: ‘If ye fulfil the royal law according to the scripture, Thou shalt love thy neighbour as thyself, ye do well’ (James 2:8). According to the scripture, ‘Thou shalt love thy neighbour as thyself.’ That is the inspired summary of the second table of the law, so James is talking about the Ten Commandments. Furthermore he says, ‘For whosoever shall keep the whole law, and yet offend in one point, he is guilty of all’ (James 2:10), and he goes on to quote the Ten Commandments.