6:2 Honour thy father and mother. Paul here implicitly endorses all ten of God’s commandments to Israel, applying them to Christians as well as Jews. The fifth commandment (Exodus 20:12; Deuteronomy 5:16) is actually the only commandment accompanied by a specific earthly promise. Obedience and honor to those who gave them birth and life is regarded as a virtue among all nations and religions; how much more should this be true in the case of children whose parents have led them into spiritual birth and life as well!
6:4 nurture and admonition. “Nurture” (Greek paideia) is the same as “chastening” in Hebrews 12:5,7, and “instruction” in II Timothy 3:16. It has particular reference to child-training, carried out with both firmness and gentleness as needed in each particular case. “Admonition” (Greek nouthesia) means literally “putting in mind”; thus “admonition of the Lord” implies teaching the Lord’s ways through His Word. Note that both—instruction through actions and instruction through verbal teaching—are primarily the responsibility of the father, although others (especially the mother—note, e.g., Proverbs 1:8) may be called upon by him to participate in the child-training activities. It is significant that the first reference in the Bible to teaching has to do with Abraham’s responsibility to bring up his own son in the nurture and admonition of the Lord (Genesis 18:19).