Charles H. Spurgeon on Psalms 73:2

Here begins the narrative of a great soul battle, a spiritual Marathon, a hard and well fought field, in which the half defeated became in the end wholly victorious. But as for me. He contrasts himself with his God who is ever good; he owns his personal want of good, and then also compares himself with the clean in heart, and goes on to confess his defilement. The Lord is good to his saints, but as for me, am I one of them? Can I expect to share his grace? Yes, I do share it; but I have acted an unworthy part, very unlike one who is truly pure in heart. My feet were almost gone. Errors of heart and head soon affect the conduct. There is an intimate connection between the heart and the feet. Asaph could barely stand, his uprightness was going, his knees were bowing like a falling wall. When men doubt the righteousness of God, their own integrity begins to waver. My steps had well nigh slipped. Asaph could make no progress in the good road, his feet ran away from under him like those of a man on a sheet of ice. He was weakened for all practical action, and in great danger of actual sin, and so of a disgraceful fall. How ought we to watch the inner man, since it has so forcible an effect upon the outward character. The confession in this case is, as it should be, very plain and explicit.