Charles H. Spurgeon on Psalms 73:1

Even to such as are of a clean heart. Purity of heart is the characteristic note of God's people. Heart purity denominates us the Israel of God; it makes us of Israel indeed; "but all are not Israel which are of Israel." Ro 9:6. Purity of heart is the jewel which is hung only upon the elect. As chastity distinguishes a virtuous woman from an harlot, so the true saint is distinguished from the hypocrite by his heart purity. This is like the nobleman's star or garter, which is a peculiar ensign of honour, differing him from the vulgar; when the bright star of purity shineth in a Christian's heart it doth distinguish him from the formal professor. . . . God is good to the pure in heart. We all desire that God should be good to us; it is the sick man's prayer: "The Lord be good to me." But how is God good to them? Two ways.

1. To them that are pure all things are sanctified, Tit 1:15: "To the pure all things are pure; " estate is sanctified, relations are sanctified; as the temple did sanctify the gold and the altar did sanctify the offering. To the unclean nothing is clean; their table is a snare, their temple devotion a sin. There is a curse entailed upon a wicked man (De 28:16), but holiness removeth the curse, and cuts off the entail: "to the pure all things are pure."

2. The clean hearted have all things work for their good. Ro 8:28. Mercies and afflictions shall turn to their good; the most poisonous drugs shall be medicinal; the most cross providence shall carry on the design of their salvation. Who, then, would not be clean on heart? Thomas Watson.