Du'a' or `supplication' is closely connected to dhikr , such that it is often difficult to make a distinction between the two. The term means literally `to call upon' and it is commanded by the Qur'an in several suggestive verses, including the following:
Supplicate your Lord humbly and secretly; He loves not transgressors. (7:55)
Supplicate Allah or supplicate the All-merciful. Whichever you supplicate - to Him belong the most beautiful names. (17:110)
Supplicate God, making your religion His sincerely, though the unbelievers be averse. (40:14)
Your Lord has said: `Supplicate Me and I will respond to you. Surely those who wax too proud to worship Me shall enter Gehenna utterly abject.' (40:60)
And when My servants question thee concerning Me - I am near to respond to the supplication of the supplicator when he supplicates Me. (2:186)