KNOW THAT THE purpose of du‘ā’ calls for presence of heart, as has been explained earlier. The proofs of this are too numerous to count, and the knowledge of this is too evident to discuss. We will cite one hadith on the subject in order to gain the blessing.
We relate in the book of at-Tirmidhī that Abū Hurayrah 
related that the Messenger of Allah 
said: “Supplicate to Allah while you feel certain of acceptance; and know that Allah 
does not respond to the du‘ā’ of a forgetful, distracted heart.” [1].The isnād has weakness in it.
related that the Messenger of Allah said: “Supplicate to Allah while you feel certain of acceptance; and know that Allah does not respond to the du‘ā’ of a forgetful, distracted heart.” [1].The isnād has weakness in it.References
[1] At-Tirmidhī (3474).