And they were commanded not, but that they should worship Allâh, and worship none but Him Alone (abstaining from ascribing partners to Him), and perform As-Salât (Iqâmat-as-Salât) and give Zakât: and that is the right religion. (Al-Baiyinah 98:5)

Narrated 'Umar bin Al-Khattab (May Allah be pleased with him), reported: Messenger of Allah (sallallahu ‘alayhi wasalam) said, "The deeds are considered by the intentions, and a person will get the reward according to his intention. So whoever emigrated for Allah and His Messenger, his emigration will be for Allah and His Messenger; and whoever emigrated for worldly benefits or for a woman to marry, his emigration would be for what he emigrated for". [Al-Bukhari and Muslim].

 Al-Fudayl b. ‘Ayyâd [187H] said: “Allah ‘azza wa jalla accepts only those deeds which are both correct and sincere (pure). If the deed is done correctly but not sincerely, it will not be accepted. And if it is sincere but not correct, it will not be accepted.” He was asked, “Abû ‘Alî! What is the sincere and correct deed?” He replied, “The sincere deed is one that is done only for Allah ‘azza wa jall. And the correct deed is one done according to the Sunnah.”