God's justice and His power are inseparable; 'tis in vain we invoke His power in an unjust cause. We are to have our souls pure and clean, at that moment at least wherein we pray to Him, and purified from all vicious passions; otherwise we ourselves present Him the rods wherewith to chastise us; instead of repairing anything we have done amiss, we double the wickedness and the offence when we offer to Him, to whom we are to sue for pardon, an affection full of irreverence and hatred. Which makes me not very apt to applaud those whom I observe to be so frequent on their knees, if the actions nearest to the prayer do not give me some evidence of amendment and reformation
Book I, ch. 56. Of Prayers - Essais (1595)