John Gill Commentary Proverbs 6:21

"Bind them continually upon thy heart; Tie them about thy neck." — Proverbs 6:21 (ASV)

Bind them continually upon your heart
Not upon the head or arm, as the words of the law were to be bound, (Deuteronomy 6:3) ; to which there seems to be an allusion; and which may confirm the sense of the words given, that this respects the law of God itself, and the precepts of it, instructed in by parents; but they should be bound upon the heart, and have an abiding place in the understanding, affections, memory, and will; [and] tie them about your neck ;
as an ornament, instead of a necklace of pearl, or chains of gold; they should be so far from being thought burdensome and troublesome, that they should be reckoned comely and graceful; see (Proverbs 1:9) (Proverbs 3:3Proverbs 3:22) .