In wicked and ungodly men, sin is with them as their nature, as poison is in a toad; but though the saints have sin in them, yet it is in them as their sickness, and they have a contrary nature besides their sinful nature. They have a sinful nature, but they are partakers of the divine nature, and that opposes the sinful nature as fire does water. The saints have that principle contrary to sin as fire is to water, and it is impossible but that principle within them must be consuming their sin and so purity them.
Jeremiah Burroughs in Hope, pg. 45