I blogged over at Crossway on how adults are commanded to honor their parents.
Though parents may quote it to small children, the primary audience of the fifth command is adult children. It is found in the middle of a list of commands clearly addressed to adults, targeting issues that are, developmentally speaking, primarily the concerns of adulthood. Small children, though certainly sinners, do not generally carve graven images, plot murderous acts, or bear credible false witness against a neighbor. Note the clue to the audience in the blessing that accompanies the command: longevity of life. We might paraphrase the fifth commandment as “Adult children, honor your aging parents whose days have been long upon the land, that your days might be long as well.”