Charles H. Spurgeon on Psalms 119:5

O that, etc. In the former verse the prophet David observes the charge which God gives, and that is, that his commandments be diligently kept: here, then, he observes his own weakness and insufficiency to discharge that great duty, and therefore, as one by the spirit desirous to discharge it, and yet by the flesh not able to discharge it, he breaketh out into these words, O that my ways were directed, etc. Much like unto a child that being commanded to take up some great weight from the ground, is willing to do it, though not able to do it: or a sick patient advised to walk many turns in his chamber, finds a desire in his heart, though inability in his body to do that which he is directed unto. Richard Greenham.