O how love I thy law! - This commences a new division of the Psalm, indicated by the Hebrew letter Mem (מ m, “m”). The expression here, “O how love I thy law,” implies intense love - as if a man were astonished at the fervour of his own emotion. His love was so ardent that it was amazing and wonderful to himself - perhaps wonderful that he, a sinner, should love the law of God at all; wonderful that he should ever have been brought so to love a law which condemned himself. Any man who reflects on what his feelings are by nature in regard to religion, will be filled with wonder that he loves it at all; all who are truly religious ought to be so filled with love to it, that it will be difficult for them to find words to express the intensity of their affection.
It is my meditation all the day - See the notes at Psalms 1:2.