It was when the Israelites were in a condition of outward ease and security that they were led into sin. They failed to keep God ever before them, they neglected prayer and cherished a spirit of self-confidence. Ease and self-indulgence left the citadel of the soul unguarded, and debasing thoughts found entrance. It was the traitors within the walls that overthrew the strongholds of principle and betrayed Israel into the power of Satan. It is thus that Satan still seeks to compass the ruin of the soul. A long preparatory process, unknown to the world, goes on in the heart before the Christian commits open sin. The mind does not come down at once from purity and holiness to depravity, corruption, and crime. It takes time to degrade those formed in the image of God to the brutal or the satanic. By beholding we become changed. By the indulgence of impure thoughts man can so educate his mind that sin which he once loathed will become pleasant to him.
– Patriarchs and Prophets, pg. 459