Sunan an-Nasai Book 47, Hadith 5030

أَخْبَرَنَا مُحَمَّدُ بْنُ قُدَامَةَ قَالَ حَدَّثَنَا جَرِيرٌ عَنْ عُمَارَةَ بْنِ الْقَعْقَاعِ عَنْ أَبِي زُرْعَةَ عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ تَضَمَّنَ اللَّهُ عَزَّ وَجَلَّ لِمَنْ خَرَجَ فِي سَبِيلِهِ لَا يُخْرِجُهُ إِلَّا الْجِهَادُ فِي سَبِيلِي وَإِيمَانٌ بِي وَتَصْدِيقٌ بِرُسُلِي فَهُوَ ضَامِنٌ أَنْ أُدْخِلَهُ الْجَنَّةَ أَوْ أُرْجِعَهُ إِلَى مَسْكَنِهِ الَّذِي خَرَجَ مِنْهُ نَالَ مَا نَالَ مِنْ أَجْرٍ أَوْ غَنِيمَةٍ

It was narrated that Abu Hurairah said:"The Messenger of Allah [SAW] said: 'Allah, the Mighty and Sublime, has guaranteed to the one who goes out in His cause, 'and he does not go out for any other purpose except Jihad in My cause and faith in Me, believing in My Messengers, but he is guaranteed that I will admit him to Paradise or I will send him back to his dwelling from which he set out, having acquired whatever he acquired of reward or spoils of war