John Gill Commentary Exodus 20:12

"Honor thy father and thy mother, that thy days may be long in the land which Jehovah thy God giveth thee." — Exodus 20:12 (ASV)

Honour your father and your mother ,
&c] Which is the fifth commandment of the decalogue, but is the first commandment with promise, as the apostle says, (Ephesians 6:2) and is the first of the second table: this, though it may be extended to all ancestors in the ascending line, as father's father and mother, mother's father and mother and to all such who are in the room of parents, as step-fathers and step-mothers, guardians, nurses and to all superiors in dignity and office, to kings and governors, to masters, ministers, and magistrates; yet chiefly respects immediate parents, both father and mother, by showing filial affection for them, and reverence and esteem of them, and by yielding obedience to them, and giving them relief and assistance in all things in which they need it; and if honour, esteem, affection, obedience, and reverence, are to be given to earthly parents, then much more to our Father which is in heaven, (Malachi 1:6) (Hebrews 12:9)

that your days may be long upon the land which the Lord your God gives
you ;
that is, the land of Canaan, which he had given by promise to your fathers, and was now about to put them, your posterity, into the possession of: this further confirms the observation made, that this body of laws belonged peculiarly to the people of Israel: long life in any place or land is a blessing in itself, not always enjoyed by obedient children, though obedience to parents often brings the judgments of God on persons; so that they sometimes die an untimely or an uncommon death, as in the case of the rebellious son, for whom a law was provided in Israel, and Absalom and others, see (Leviticus 20:9) (Deuteronomy 21:18) (2 Samuel 18:14) (Proverbs 30:17)

Aben Ezra takes the word to be transitive, and so the words may be read, "that they may prolong your days"; or, "cause your days to be prolonged"; meaning either that the commandments, and keeping of them, may be the means of prolonging the days of obedient children, according to the divine promise; or that they, their father and mother, whom they harbour and obey, might, by their prayers for them, be the means of obtaining long life for them; or else that they, Father, Son, and Spirit, may do it, though man's days, strictly speaking, cannot be shortened or lengthened beyond the purpose of God, see (Job 14:5) the Septuagint version inserts before this clause another, "that it may be well with you", as in (Deuteronomy 5:16) and which the apostle also has, (Ephesians 6:3) and where, instead of this, the words are, "and you may live long on the earth"; accommodating them the better to the Gentiles, to whom he writes.