God, Glorified be He, has compared those who do not answer the call of His Messenger to the people of the graves.  This is the best comparison because their bodies are the graves for their hearts, for their hearts have died and have been buried in their bodies.

God said: Surely Allah makes whom He pleases hear, and you cannot make those hear who are in the graves. [Q. Fāṭir, 35: 22]

Ibn al-Qayyim (d. 751/1350), Ighathat al-Lahfān min maṣāyid al-Shaytān