Sahih Bukhari Volume 7, Book 67, Hadith 5072

حَدَّثَنَا يَحْيَى بْنُ قَزَعَةَ، حَدَّثَنَا مَالِكٌ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنْ مُحَمَّدِ بْنِ إِبْرَاهِيمَ بْنِ الْحَارِثِ، عَنْ عَلْقَمَةَ بْنِ وَقَّاصٍ، عَنْ عُمَرَ بْنِ الْخَطَّابِ ـ رضى الله عنه ـ قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم ‏"‏ الْعَمَلُ بِالنِّيَّةِ، وَإِنَّمَا لاِمْرِئٍ مَا نَوَى، فَمَنْ كَانَتْ هِجْرَتُهُ إِلَى اللَّهِ وَرَسُولِهِ فَهِجْرَتُهُ إِلَى اللَّهِ وَرَسُولِهِ صلى الله عليه وسلم وَمَنْ كَانَتْ هِجْرَتُهُ إِلَى دُنْيَا يُصِيبُهَا أَوِ امْرَأَةٍ يَنْكِحُهَا، فَهِجْرَتُهُ إِلَى مَا هَاجَرَ إِلَيْهِ ‏"‏‏

Narrated By 'Umar bin Al-Khattab : The Prophet said, "The rewards (of deeds) are according to the intention, and everybody will get the reward for what he has intended. So whoever emigrated for Allah's and His Apostle's sake, his emigration was for Allah and His Apostle; and whoever emigrated for worldly benefits, or to marry a woman, then his emigration was for the thing for what he emigrated for."