Charles H. Spurgeon on Psalms 119:66

Teach me good judgment and knowledge, etc. Literally it may be rendered thus, Teach me goodness, discernment and knowledge; for I have believed or confided in thy commandments. In our system of divine things, we might be inclined to place knowledge and discernment first, as begetting the "goodness." But it is a well ascertained fact, that the intellectual and moral powers are reciprocal that the moral also give strength to the intellectual. Moreover, it is only the spiritual man that discerns the things of God. The state of being spiritually minded, and also conversant with divine things, gives a rigour and breadth to the intellect itself, that remarkably appears in the lives of eminent men. And if you remark that some have been eminent who were devoid of spiritual qualities, the reply might be How much more eminent would they have been had they possessed these qualities. The petition is, "Teach me goodness, discernment, and knowledge." The principle of pleasing God may be within, and yet the mind may require to be enlightened in all duty; and again, though all duty be known, we may require spiritual discernment to see and feel it aright. John Stephen.