It was narrated from Abu Hurairah that the Messenger of Allah (ﷺ) said: "Allah, the Mighty and Sublime, has guaranteed to the one who strives in His cause, only going out for Jihad in His cause, and believing in His Word, that He will admit him to Paradise, or bring him back to his home from which he emerged, with whatever he has earned of reward, or spoils of war."
Source: sunnah.com
Other translations
Arabic
أَخْبَرَنَا مُحَمَّدُ بْنُ سَلَمَةَ، وَالْحَارِثُ بْنُ مِسْكِينٍ، قِرَاءَةً عَلَيْهِ وَأَنَا أَسْمَعُ، عَنِ ابْنِ الْقَاسِمِ، قَالَ حَدَّثَنَا مَالِكٌ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " تَكَفَّلَ اللَّهُ عَزَّ وَجَلَّ لِمَنْ جَاهَدَ فِي سَبِيلِهِ لاَ يُخْرِجُهُ إِلاَّ الْجِهَادُ فِي سَبِيلِهِ وَتَصْدِيقُ كَلِمَتِهِ بِأَنْ يُدْخِلَهُ الْجَنَّةَ أَوْ يَرُدَّهُ إِلَى مَسْكَنِهِ الَّذِي خَرَجَ مِنْهُ مَعَ مَا نَالَ مِنْ أَجْرٍ أَوْ غَنِيمَةٍ " .
sunnah.com