Abu Hurairah said:

"I heard the Messenger of Allah ﷺ say: 'The parable of Mujahid (who strives in the cause of Allah) - and Allah knows best who strives in teh cause of Allah - is that of one who fasts and prays Qiyam (continually). Allah has promised Mujahid (who strives in His cause), that He will either cause him to die and admit him to paradise, or, He will bring him back safely with whatever he had earned of reward or spoils of war.'"

أَخْبَرَنِي عَمْرُو بْنُ عُثْمَانَ بْنِ سَعِيدِ بْنِ كَثِيرِ بْنِ دِينَارٍ، قَالَ حَدَّثَنَا أَبِي، عَنْ شُعَيْبٍ، عَنِ الزُّهْرِيِّ، قَالَ أَخْبَرَنِي سَعِيدُ بْنُ الْمُسَيَّبِ، قَالَ سَمِعْتُ أَبَا هُرَيْرَةَ، قَالَ سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ " مَثَلُ الْمُجَاهِدِ فِي سَبِيلِ اللَّهِ - وَاللَّهُ أَعْلَمُ بِمَنْ يُجَاهِدُ فِي سَبِيلِ اللَّهِ - كَمَثَلِ الصَّائِمِ الْقَائِمِ وَتَوَكَّلَ اللَّهُ لِلْمُجَاهِدِ فِي سَبِيلِهِ بِأَنْ يَتَوَفَّاهُ فَيُدْخِلَهُ الْجَنَّةَ أَوْ يَرْجِعَهُ سَالِمًا بِمَا نَالَ مِنْ أَجْرٍ أَوْ غَنِيمَةٍ " .