Sahih Bukhari | Volume 5 | Hadith Number 238

Narrated by 'Umar
I heard the Prophet 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."