Jami` at-Tirmidhi, Hadith 1620 ⓘ
Narrated Anas bin Malik: "The Messenger of Allah said: meaning: Allah Mighty and Sublime is He says: 'The Mujahid in My cause, he has guarantee fro Me. If I I seize him, I cause him to inherit Paradise, and if I return him, I return him with a reward or spoils of war.'" [He said:] This Hadith is Gharib Sahih from this route.
حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ بَزِيعٍ، حَدَّثَنَا الْمُعْتَمِرُ بْنُ سُلَيْمَانَ، حَدَّثَنِي مَرْزُوقٌ أَبُو بَكْرٍ، عَنْ قَتَادَةَ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَعْنِي " يَقُولُ اللَّهُ عَزَّ وَجَلَّ الْمُجَاهِدُ فِي سَبِيلِ اللَّهِ هُوَ عَلَىَّ ضَامِنٌ إِنْ قَبَضْتُهُ أَوْرَثْتُهُ الْجَنَّةَ وَإِنْ رَجَعْتُهُ رَجَعْتُهُ بِأَجْرٍ أَوْ غَنِيمَةٍ " . قَالَ هُوَ صَحِيحٌ غَرِيبٌ مِنْ هَذَا الْوَجْهِ .
also referenced under: Book 22, Hadith 2 (In-Book) & Volume 3, Book 20, Hadith 1620 (DarusSalam)