WHAT ONE SIN WILL DO.
THERE is but one crack in the lantern, and the wind has found it out, and blown out the candle. How great a mischief one unguarded point in our character may cause us? One spark blew up the magazine, and shook the world for miles around. One leak sank the ship, and drowned all on board. One wound may kill the body-and sin destroy the soul.
It matters little how carefully the rest of the lantern is protected, the one point which is damaged is quite sufficient to admit the wind; and so it matters little how zealous a man may be in a thousand things, if he tolerates one darling sin; Satan will find out the flaw, and destroy all his hopes. The strength of a chain is to be measured, not by its strongest but by its weakest link; for if the weakest snaps, what is the use of the rest? Satan is a very close observer, and knows exactly where our weak points are. We have need of very much watchfulness, and we have great cause to bless our merciful Lord, who prayed for us that our faith fail not. Either our pride, our sloth, our ignorance, our anger, or our lust, will prove our ruin unless grace interposes; any one of our senses may admit the foe, yea, our very virtues and graces maybe gates of entrance to our enemies.
Spurgeon.