Psalms 51:2

Wash me throughly from mine iniquity, and cleanse me from my sin.

Ver. 2. Wash me throughly from mine iniquity] Heb. Multiply, wash me; so Isaiah 55:7. God is said to multiply pardon as much as we multiply sin. David apprehended his sin so exceeding sinful, his stain so inveterate, so engrained, that it would hardly be ever gotten out till the cloth were almost rubbed to pieces; that God himself would have somewhat to do to do it. He had been in a deep ditch, Proverbs 23:27, and was pitifully defiled; he therefore begs hard to be thoroughly rinsed, to be bathed in that blessed fountain of Christ's blood, that is opened for sins and for uncleanness, Zechariah 13:1; to be cleansed not only from outward defilements, but from his swinish nature; for though a swine be washed never so clean, if she retain her nature, she will be ready to wallow in the next guzzle. The time of our being here is αιων λουτροφορος, as Nazianzen calleth it, i.e. our washing time. Wash thy heart, O Jerusalem, that thou mayest be clean, Jeremiah 4:14, not by thinking to set off with God, and to make amends by thy good deeds for thy bad; this is but lutum luto purgare, to wash off one filth with another; but by the practice of mortification, and by faith in Christ's meritorious passion; for he hath washed us from our sins in his own blood, Revelation 1:5. Other blood defileth, but this purifieth from all pollutions of flesh and spirit, 1 John 1:7 .

And cleanse me from my sin] In like manner as the leper under the law was cleansed. Leprosy, frenzy, heresy, and jealousy, are by men counted incurable; Sed omnipotenti medico nullus insanabilis occurrit morbus, saith Isidore, to an Almighty physician no disease is incurable. There is indeed a natural Novatianism in the timorous consciences of convinced sinners, to doubt and question pardon for sins of apostasy, and falling after repentance; but there need be no such doubting, since God, who hath bidden us to forgive a repenting brother seventy times seven times in one day, will himself much more. All sins and blasphemies shall be forgiven to the sons of men, &c., Matthew 12:31 .