Albert Barnes Commentary Psalms 119:64

"The earth, O Jehovah, is full of thy lovingkindness: Teach me thy statutes. TETH." — Psalms 119:64 (ASV)

The earth, O Lord, is full of thy mercy - Full of the proofs of your goodness and compassion. See the notes at Psalms 33:5. This is the expression of a heart full of love to God and to his word. In such a state of mind as the psalmist was in, the goodness of God is seen everywhere. The best preparation for seeing evidence that God is good is a heart full of love. Then the proofs of that love spring up on every side - as when we truly love a friend we find constant proofs of his excellency of character.

Teach me thy statutes - I desire to see more and more of your law. You are so gracious and merciful, the evidence of your goodness is so widespread around me, that it leads me to desire to see more and more of yourself and your law.