Charles H. Spurgeon on Psalms 119:40

Behold, I have longed after, etc. This is given as a more intense form of the statement which he had just made, that he esteemed the judgments to be good. They were so good that he longed after them. Blot only so, but he desired to long after them even more. Thus he prays for even more life and rigour in pursuing the path which they pointed out Quicken me in thy righteousness. He who really longs after divine truth, mourns that he does not long more. When the heart has no love, thee mind has no light, and can only judge the precepts erroneously. "The pure in heart" see better with the mind than can the impure. "Unto the upright there ariseth light in the darkness." Love so enlarges discernment that he who really loves often finds that his judgment of the blessedness of truth has outstripped even his longing for it. Hence it is the quick who cry, "Quicken me"; it is those who have living desires who pray for yet more life in the way of righteousness.