Satan and devil flow in body like blood
The devil has full control over man’s heart, then when man remembers Allah he withdraws, and when he neglects to remember Him, he whispers to him.
He knows whether he is remembering Allah or is neglecting to remember Him, and he knows the whims and desires of his heart and makes them appear attractive to him.
It is proven in al-Saheeh, in the hadeeth (narration) mentioned by Safiyyah (may Allah be pleased with her) that the Prophet (peace and blessings of Allah be upon him) said: “The shaytan flows through the sons of Adam like blood.”
The closeness of the angels and the shaytan to the heart of the son of Adam is something that is confirmed in many reports, whether the person is a believer or a disbeliever. Majmoo’ al-Fatawa.
