Let them not depart from thine eyes; i.e. keep them constantly in view as the guide of the whole conduct. These words are a repetition of Proverbs 3:21, just as the latter part of the verse reproduces the thought of Proverbs 2:1.
Depart. The hiph. yallizu is here used instead of the kal yaluzu of Proverbs 3:21, but has the same force. In the midst of thine heart; i.e. in its inmost recesses; there the words and sayings are to be guarded as a man guards a treasure stowed away in the inmost chambers of a house.
The expression implies cherishing them with an internal affection. The terms of the verse may be illustrated by Deuteronomy 6:6, Deuteronomy 6:8, "And these words, which I command thee this day, shall be in thine heart.
And thou shalt bind them for a sign upon thine hand, and they shall be as frontiers between thine eyes."