Psalms 51:10

Create in me a clean heart, O God; and renew a right spirit within me.

Ver. 10. Create in me a clean heart, O God] His heart was woefully soiled with the filth of sin and the work of grace interrupted; he therefore prayeth God to interpose and begin it again, to set him up once more, to rekindle those sparks of the spirit that lay almost quite smothered; to put forth his Almighty power for that purpose, to farm that Augaean stable of his heart; to sanctify him throughout in spirit, soul, and body; and to keep him blameless unto the coming of his Son 1 Thessalonians 5:23 .

And renew a right spirit within me] Or, a firm spirit, firm for God, able to resist the devil, steadfast in the faith, and to abide constant in the way that is called holy.