The context obviously addresses children and parents. Paul makes it clear that children have a responsibility before God and that keeping the commandment has definite benefits for them to anticipate receiving. This is in agreement with Deuteronomy 4:39-40.
One of the benefits he mentions is the prospect of long life, which also contains an implication of prosperity. Not the least of the additional benefits is the gradual development of understanding and wisdom garnered from the parents, which themselves help to produce long life and prosperity. Thus, in an overall sense, he is reminding children that obedience to truth has its rewards.
Is there an age at which or a circumstance under which the child's responsibility to honor his parents undergoes a change? The answer is both "Yes" and "No," which is why Paul qualifies his charge to children. His qualification is contained within the phrase "in the Lord." It connotes what is within the boundaries of the Lord's way. In all cases, the responsibility to honor one's parents diminishes when a child marries, and his first attention must be given to the spouse. Cleaving to the spouse trumps the honoring of parents. Paul qualifies this a step further by implying that, if the parents demand submission beyond the bounds of Christian conduct, that is, not "in the Lord"—such as commanding a child to give up the Sabbath, lie in their behalf, steal for them, or bow down to an idol—in such cases the child's choice should be to submit to Christ rather than to his parents. Submitting to God's commands trumps submitting to parent's commands that are beyond what God commands us to do in order to stay "in the Lord."
John W. Ritenbaugh
The Fifth Commandment
Obeying the fifth commandment automatically builds habits and character that promote long life (Proverbs 4:10-11). A child trained in biblical principles and God's way of life will avoid recklessness, violence, immorality, and rebellion against authority that often result in premature death.
Martin G. Collins
The Fifth Commandment
The command to honor parents applies to all of us all our lives. But here, as in Colossians 3:20, children should obey their parents in all things "in the Lord."
The apostle is not saying a child must break the Ten Commandments if a parent orders him to so. Children should obey "in the Lord," that is, obey commands that agree with the will of God. Most younger children cannot grasp whether a parental order conforms to God's will. But as they age, they need to understand that they, too, are under the authority of the living Christ.
Though parents have a huge part in starting children off on the right foot regarding this commandment, the greater responsibility for keeping it rests with the child. At some point, children need to realize that their submission to parents is an act of faith in Christ. Their required obedience is not based on any arbitrary power held by parents but on a higher law to which parents are also subject. Parents have a primary responsibility to teach their children to discipline, govern, or control themselves under God's law. Children must learn that they cannot always do what they want when they want, or have what they want when they want it.
Keeping this commandment brings great benefits, as Paul reminds us in Ephesians 6:2, "which is the first commandment with promise." The promise of blessing for keeping it is written right into the commandment! God promises, "That it may be well with you and you may live long on the earth."
This blessing has at least two parts. Obedience to parental admonitions, gained from years of experience living in this difficult and dangerous world, results in the building of knowledge, character, and habits of avoiding recklessness, lawlessness, violence, wrong companionships, and rebellion against authority. These often result in untimely and violent death at a young age. Virtually every year this comes to the fore when statistics show that accidents are our children's number one killer.
The second and ultimate meaning is that, in honoring our spiritual Father, God, we receive spiritual blessings far above long physical life. From the loving relationship between God and his child will arise eternal life, which God will give as a gift to a son who pleases Him.
John W. Ritenbaugh
The Fifth Commandment (1997)
Other Forerunner Commentary entries containing Ephesians 6:2: