Sahih Bukhari Volume 4, Book 57, Hadith 3124

حَدَّثَنَا إِسْمَاعِيلُ، قَالَ حَدَّثَنِي مَالِكٌ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ تَكَفَّلَ اللَّهُ لِمَنْ جَاهَدَ فِي سَبِيلِهِ، لاَ يُخْرِجُهُ إِلاَّ الْجِهَادُ فِي سَبِيلِهِ وَتَصْدِيقُ كَلِمَاتِهِ، بِأَنْ يُدْخِلَهُ الْجَنَّةَ، أَوْ يَرْجِعَهُ إِلَى مَسْكَنِهِ الَّذِي خَرَجَ مِنْهُ ‏{‏مَعَ مَا نَالَ‏}‏ مِنْ أَجْرٍ أَوْ غَنِيمَةٍ ‏"‏‏

Narrated By Abu Huraira : Allah's Apostle said, "Allah guarantees him who strives in His Cause and whose motivation for going out is nothing but Jihad in His Cause and belief in His Word, that He will admit him into Paradise (if martyred) or bring him back to his dwelling place, whence he has come out, with what he gains of reward and booty."