Psalms 51:6

Psalms 51:6. Behold, thou desirest truth in the inward parts: and in the hidden part thou shalt make me to know wisdom.

Ah, friends, that is the troublesome part of the matter! We might be able to rectify the external wrong, and to reform our outward actions; but who can make his heart clean? You can prune the tree, you may cut it to almost any shape you like; but you cannot make the deadly tree bring forth healthy fruit, you cannot change the sap, or alter the nature of the tree’s roots. What but a power divine can do this? "In the hidden part thou shalt make me to know wisdom;" but nobody else can.