Sahih Muslim 1876 c
It has been narrated on the authority of Abu Huraira who said:
Allah has undertaken to provide for one who leaves his home (only) to fight for His cause and to affirm the truth of His word; Allah will either admit him to Paradise or will bring him back home from where he had come out, with his reward and booty.
وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى، أَخْبَرَنَا الْمُغِيرَةُ بْنُ عَبْدِ الرَّحْمَنِ الْحِزَامِيُّ، عَنْ أَبِي الزِّنَادِ،
 عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏
"‏ تَكَفَّلَ اللَّهُ لِمَنْ جَاهَدَ
 فِي سَبِيلِهِ لاَ يُخْرِجُهُ مِنْ بَيْتِهِ إِلاَّ جِهَادٌ فِي سَبِيلِهِ وَتَصْدِيقُ كَلِمَتِهِ - بِأَنْ يُدْخِلَهُ الْجَنَّةَ أَوْ
 يَرْجِعَهُ إِلَى مَسْكَنِهِ الَّذِي خَرَجَ مِنْهُ مَعَ مَا نَالَ مِنْ أَجْرٍ أَوْ غَنِيمَةٍ ‏"‏ ‏.‏