Tafsir Ibn Kathir -> Surah An-Nisa -> The Encouragement to Participation in Jihad

Allah then said,

﴿فَلْيُقَاتِلْ﴾

(So fight) the believer with an aversion (to fighting),

﴿فِى سَبِيلِ اللَّهِ الَّذِينَ يَشْرُونَ الْحَيَوةَ الدُّنْيَا بِالاٌّخِرَةِ﴾

(those who trade the life of this world with the Hereafter) referring to those sell their religion for the meager goods of the world, and they only do this because of their disbelief and lack of faith. Allah then said;

﴿وَمَن يُقَـتِلْ فِى سَبِيلِ اللَّهِ فَيُقْتَلْ أَو يَغْلِبْ فَسَوْفَ نُؤْتِيهِ أَجْراً عَظِيماً﴾

(And whoever fights in the cause of Allah, and is killed or gets victory, We shall bestow on him a great reward.) meaning, whoever fights in the cause of Allah, whether he was killed or triumphant, he will earn an immense compensation and a great reward with Allah. The Two Sahihs recorded,

«وَتَكَفَّلَ اللهُ لِلْمُجَاهِدِ فِي سَبِيلِهِ، إِنْ تَوَفَّاهُ أَنْ يُدْخِلَهُ الْجَنَّةَ، أَوْ يَرْجِعَهُ إِلى مَسْكَنِهِ الَّذِي خَرَجَ مِنْهُ، بِمَا نَالَ مِنْ أَجْرٍ أَوْ غَنِيمَة»

(Allah has guaranteed the Mujahid in His cause that He will either bring death to him, admitting into Paradise; or, He will help him return safely to his home with whatever reward and booty he gained.)

﴿وَمَا لَكُمْ لاَ تُقَـتِلُونَ فِى سَبِيلِ اللَّهِ وَالْمُسْتَضْعَفِينَ مِنَ الرِّجَالِ وَالنِّسَآءِ وَالْوِلْدَنِ الَّذِينَ يَقُولُونَ رَبَّنَآ أَخْرِجْنَا مِنْ هَـذِهِ الْقَرْيَةِ الظَّـلِمِ أَهْلُهَا وَاجْعَلْ لَّنَا مِن لَّدُنْكَ وَلِيّاً وَاجْعَلْ لَّنَا مِن لَّدُنْكَ نَصِيراً - الَّذِينَ ءَامَنُواْ يُقَـتِلُونَ فِى سَبِيلِ اللَّهِ وَالَّذِينَ كَفَرُواْ يُقَـتِلُونَ فِى سَبِيلِ الطَّـغُوتِ فَقَـتِلُواْ أَوْلِيَاءَ الشَّيْطَـنِ إِنَّ كَيْدَ الشَّيْطَـنِ كَانَ ضَعِيفاً ﴾

(75. And what is wrong with you that you fight not in the cause of Allah, and for those weak, ill-treated and oppressed among men, women, and children, whose cry is: "Our Lord! Rescue us from this town whose people are oppressors; and raise for us from You one who will protect, and raise for us from You one who will help.'') (76. Those who believe, fight in the cause of Allah, and those who disbelieve, fight in the cause of the Taghut. So fight against the friends of Shaytan; ever feeble indeed is the plot of Shaytan.)