Sahih Muslim 1865a
It has been narrated on the authority of Abu Sa'id al-Khudari that a Bedouin asked the Messenger of Allah ﷺ about Migration. He replied: Do you talk of Hijra? The affair of Hijra is very difficult. But have you got camels? The bedouin said: Yes. He asked: Do you pay the poor-rate payable on their account? He replied: Yes. He (the Holy Prophet) said: Go on doing good deeds (across the seas), for surely God will not leave any of your deeds unrewarded.
وَحَدَّثَنَا أَبُو بَكْرِ بْنُ خَلاَّدٍ الْبَاهِلِيُّ، حَدَّثَنَا الْوَلِيدُ بْنُ مُسْلِمٍ، حَدَّثَنَا عَبْدُ الرَّحْمَنِ، بْنُ عَمْرٍو الأَوْزَاعِيُّ حَدَّثَنِي ابْنُ شِهَابٍ الزُّهْرِيُّ، حَدَّثَنِي عَطَاءُ بْنُ يَزِيدَ اللَّيْثِيُّ، أَنَّهُ حَدَّثَهُمْ قَالَ حَدَّثَنِي أَبُو سَعِيدٍ الْخُدْرِيُّ، أَنَّ أَعْرَابِيًّا، سَأَلَ رَسُولَ اللَّهِ ﷺ عَنِ الْهِجْرَةِ فَقَالَ " وَيْحَكَ إِنَّ شَأْنَ الْهِجْرَةِ لَشَدِيدٌ فَهَلْ لَكَ مِنْ إِبِلٍ " . قَالَ نَعَمْ . قَالَ " فَهَلْ تُؤْتِي صَدَقَتَهَا " . قَالَ نَعَمْ . قَالَ " فَاعْمَلْ مِنْ وَرَاءِ الْبِحَارِ فَإِنَّ اللَّهَ لَنْ يَتِرَكَ مِنْ عَمَلِكَ شَيْئًا " .