This is a heart with life in it, as well as illness. The former sustains it at one moment, the latter at another, and it follows whichever one of the two manages to dominate it. It has love for Allaah, faith in Him, sincerity towards Him, and reliance upon Him, and these are what give it life. It also has a craving for lust and pleasure, and prefers them and strives to experience them.
It is full of self-admiration, which can lead to its own destruction. It listens to two callers: one calling it to Allaah and His Prophet (صلى الله عليه و سلم) and the akhirah (the hereafter); and the other calling it to the fleeting pleasures of this world. It responds to whichever one of the two happens to have most influence over it at the time.
The first heart is alive, submitted to Allaah, humble, sensitive and aware; the second is brittle and dead; the third wavers between either its safety or its ruin.