Proverbs 17:6

They are so, that is, they should be so, and, if they conduct themselves worthily, they are so. 1. It is an honour to parents when they are old to leave children, and children's children, growing up, that tread in the steps of their virtues, and are likely to maintain and advance the reputation of their families. It is an honour to a man to live so long as to see his children's children (Psa 128:6; Gen 50:23), to see his house built up in them, and to see them likely to serve their generation according to the will of God. This crowns and completes their comfort in this world. 2. It is an honour to children to have wise and godly parents, and to have them continued to them even after they have themselves grown up and settled in the world. Those are unnatural children who reckon their aged parents a burden to them, and think they live too long; whereas, if the children be wise and good, it is as much their honour as can be that thereby they are comforts to their parents in the unpleasant days of their old age.

— Matthew Henry's Concise Commentary (public domain)

Prolonged posterity is a blessing, its cutting off a curse (Pro 13:22; Psa 109:13-15), hence children may glory in virtuous ancestry.

— Jamieson-Fausset-Brown Commentary (public domain)