Narrated `Umar: I heard the Prophet (peace be upon him) saying, “The reward of deeds depends on the intentions, so whoever emigrated for the worldly benefits or to marry a woman, his emigration was for that for which he emigrated, but whoever emigrated for the Sake of Allah and His Apostle, his emigration is for Allah and His Apostle.”
Sahih al-Bukhari, Vol. 5, Book 63, Hadith 124