Imam of the Taba'een, Hasan al-Basri R.A. said:
"Two thoughts roam over the soul, one from Allah, one from the enemy (Satan). Allah shows mercy on a servant who settles at the thought that comes from Him. He embraces the thought that comes from Allah, while he fights against the one from his enemy.
To illustrate the heart's mutual attraction between these two powers the Prophet SAWS said: 'The heart of a believer lies between two fingers of the Merciful' (Narrated by Muslim, Ahmad, Tirmidhi, and Ibn Majah).
The fingers stand for upheaval and hesitation in the heart.
If man follows the dictates of anger and appetite, the dominion of shaytan appears in him through idle passions [hawa] and his heart becomes the nesting-place and container of shaytan, who feeds on hawa.
If he does battle with his passions and does not let them dominate his nafs, imitating in this the character of the angels, at that time his heart becomes the resting-place of angels and they alight upon it."