Qur'an 9:111

۞ إِنَّ ٱللَّهَ ٱشْتَرَىٰ مِنَ ٱلْمُؤْمِنِينَ أَنفُسَهُمْ وَأَمْوَٰلَهُم بِأَنَّ لَهُمُ ٱلْجَنَّةَ ۚ يُقَـٰتِلُونَ فِى سَبِيلِ ٱللَّهِ فَيَقْتُلُونَ وَيُقْتَلُونَ ۖ وَعْدًا عَلَيْهِ حَقًّا فِى ٱلتَّوْرَىٰةِ وَٱلْإِنجِيلِ وَٱلْقُرْءَانِ ۚ وَمَنْ أَوْفَىٰ بِعَهْدِهِۦ مِنَ ٱللَّهِ ۚ فَٱسْتَبْشِرُوا۟ بِبَيْعِكُمُ ٱلَّذِى بَايَعْتُم بِهِۦ ۚ وَذَٰلِكَ هُوَ ٱلْفَوْزُ ٱلْعَظِيمُ

Lo! Allah hath bought from the believers their lives and their wealth because the Garden will be theirs: they shall fight in the way of Allah and shall slay and be slain. It is a promise which is binding on Him in the Torah and the Gospel and the Qur'an. Who fulfilleth His covenant better than Allah? Rejoice then in your bargain that ye have made, for that is the supreme triumph.