Charles H. Spurgeon on Psalms 30:6

In my prosperity. When all his foes were quiet, and his rebellious son dead and buried, then was the time of peril. Many a vessel founders in a calm. No temptation is so bad as tranquillity. I said, I shall never be moved. Ah! David, you said more than was wise to say, or even to think, for God has founded the world upon the floods, to show us what a poor, mutable, moveable, inconstant world it is. Unhappy he who builds upon it! He builds himself a dungeon for his hopes. Instead of conceiving that we shall never be moved, we ought to remember that we shall very soon be removed altogether. Nothing is abiding beneath the moon. Because I happen to be prosperous today, I must not fancy that I shall be in my high estate tomorrow. As in a wheel, the uppermost spokes descend to the bottom in due course, so it is with mortal conditions. There is a constant revolution: many who are in the dust today shall be highly elevated tomorrow; while those who are now aloft shall soon grind the earth. Prosperity had evidently turned the psalmist's head, or he would not have been so self confident. He stood by grace, and yet forgot himself, and so met with a fall. Reader, is there not much of the same proud stuff in all our hearts? let us beware lest the fumes of intoxicating success get into our brains and make fools of us also.