Paul, like Jesus, nowhere abrogated the law (Mt. 5:17-20). Here Paul continues to address family issues, and with respect to children and parents he quotes Dt. 5:16. What is especially significant is his comment that the 5thcommandment is the first with a promise (Cf. Dt. 6:2). What is perhaps equally significant is the nature of the promise, not heaven, as some may assume, but rather “that it may be well with you and you may live long on the earth.” Too many fundamentalists and evangelicals, and even some Reformed have a pagan view of life, that we were only born for the next life. There will certainly be a resurrection, but it will be to a new heavens and a new earth, and now there is this promise of wellness, and long life to those who obey and honour their parents, as the commandment requires.
I also disagree with those who see this commandment as the first toward our fellow human beings. Rather, I think it belongs to those concerning our direct relationship to God, for parents are uniquely his vice-regents over a godly seed, given children as gifts that they are to offer back to the Lord. It is worth noting that the command includes mother and father, and in fact Lev. 19:2 has this order, and the first mark of holiness (Lev. 19:1)! There is in fact a promise of wellness and long life given to all the covenant people who keep his law. Beyond the decalogue that Paul refers to, Moses said the same earlier to all at Dt. 4:40. Moses is careful to add that it comes after redemption (Cf. Dt. 5:1-5). Here Paul says that Fathers as the normal heads of household are directly accountable to God for the covenant seed he gives them (v. 4).