Narrated Abu Huraira: I heard Allah's Messenger (ﷺ) saying, "The example of a Mujahid in Allah's Cause-- and Allah knows better who really strives in His Cause----is like a person who fasts and prays continuously. Allah guarantees that He will admit the Mujahid in His Cause into Paradise if he is killed, otherwise He will return him to his home safely with rewards and war booty."
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا أَبُو الْيَمَانِ، أَخْبَرَنَا شُعَيْبٌ، عَنِ الزُّهْرِيِّ، قَالَ أَخْبَرَنِي سَعِيدُ بْنُ الْمُسَيَّبِ، أَنَّ أَبَا هُرَيْرَةَ، قَالَ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ " مَثَلُ الْمُجَاهِدِ فِي سَبِيلِ اللَّهِ ـ وَاللَّهُ أَعْلَمُ بِمَنْ يُجَاهِدُ فِي سَبِيلِهِ ـ كَمَثَلِ الصَّائِمِ الْقَائِمِ، وَتَوَكَّلَ اللَّهُ لِلْمُجَاهِدِ فِي سَبِيلِهِ بِأَنْ يَتَوَفَّاهُ أَنْ يُدْخِلَهُ الْجَنَّةَ، أَوْ يَرْجِعَهُ سَالِمًا مَعَ أَجْرٍ أَوْ غَنِيمَةٍ ".
sunnah.com