John Gill Commentary Proverbs 1:9

"For they shall be a chaplet of grace unto thy head, And chains about thy neck." — Proverbs 1:9 (ASV)

For they [shall be] an ornament of grace to your head
The instructions and laws of parents being attended to and obeyed by children, render them more lovely and amiable than any beautiful ornament whatever that can be put upon their heads;

and chains about your neck ;
be that to them as chains of gold are to the neck, beautify and adorn them; so good works, done in obedience to God and parents, are ornaments of great price, and preferable to any outward adorning whatever; see (1 Timothy 2:9 1 Timothy 2:10) (1 Peter 3:3 1 Peter 3:4) .

The allusions are to, and the metaphors taken from, things that are most pleasing and acceptable to children, as fine top knots and golden chains.