Sunan an-Nasai Book 47, Hadith 5029

أَخْبَرَنَا قُتَيْبَةُ قَالَ حَدَّثَنَا اللَّيْثُ عَنْ سَعِيدٍ عَنْ عَطَاءِ بْنِ مِينَاءَ سَمِعَ أَبَا هُرَيْرَةَ يَقُولُ سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ انْتَدَبَ اللَّهُ لِمَنْ يَخْرُجُ فِي سَبِيلِهِ لَا يُخْرِجُهُ إِلَّا الْإِيمَانُ بِي وَالْجِهَادُ فِي سَبِيلِي أَنَّهُ ضَامِنٌ حَتَّى أُدْخِلَهُ الْجَنَّةَ بِأَيِّهِمَا كَانَ إِمَّا بِقَتْلٍ وَإِمَّا وَفَاةٍ أَوْ أَنْ يَرُدَّهُ إِلَى مَسْكَنِهِ الَّذِي خَرَجَ مِنْهُ يَنَالُ مَا نَالَ مِنْ أَجْرٍ أَوْ غَنِيمَةٍ

Abu Hurairah said:"I heard the Messenger of Allah [SAW] say: 'Allah has promised the one who goes out in His cause 'and does not go out except with faith in Me and for Jihad in My cause,' that he is guaranteed to enter Paradise no matter how, either he is killed, or he dies, or he will be brought back to his home from which he departed having acquired whatever he acquired of reward or spoils of war