Verses with the word apply in the Old Testament (4 verses):
Psalms 90:12
So teach us to number our days, that we may apply our hearts unto wisdom.
Proverbs 2:2
So that thou incline thine ear unto wisdom, and apply thine heart to understanding;
Proverbs 22:17
Bow down thine ear, and hear the words of the wise, and apply thine heart unto my knowledge.
Proverbs 23:12
Apply thine heart unto instruction, and thine ears to the words of knowledge.