Encouraging Jihad to Defend the Oppressed
Allah encouraged His believing servants to perform Jihad in His cause and to strive hard to save the oppressed Muslims in Makkah, men, women and children who were restless because of having to remain there. This is why Allah said,
الَّذِينَ يَقُولُونَ رَبَّنَآ أَخْرِجْنَا مِنْ هَـذِهِ الْقَرْيَةِ
(whose cry is: "Our Lord! Rescue us from this town), referring to Makkah. In a similar Ayah, Allah said,
وَكَأَيِّن مِّن قَرْيَةٍ هِىَ أَشَدُّ قُوَّةً مِّن قَرْيَتِكَ الَّتِى أَخْرَجَتْكَ
(And many a town, stronger than your town which has driven you out) Allah then describes this town,
الظَّـلِمِ أَهْلُهَا وَاجْعَلْ لَّنَا مِن لَّدُنْكَ وَلِيّاً وَاجْعَلْ لَّنَا مِن لَّدُنْكَ نَصِيراً
(whose people are oppressors; and raise for us from You one who will protect, and raise for us from You one who will help) meaning, send protectors and helpers for us. Al-Bukhari recorded that Ibn `Abbas said, "I and my mother were from the oppressed (in Makkah)." Allah then said,
الَّذِينَ ءَامَنُواْ يُقَـتِلُونَ فِى سَبِيلِ اللَّهِ وَالَّذِينَ كَفَرُواْ يُقَـتِلُونَ فِى سَبِيلِ الطَّـغُوتِ
(Those who believe, fight in the cause of Allah, and those who disbelieve, fight in the cause of the Taghut. ) Therefore, the believers fight in obedience to Allah and to gain His pleasure, while the disbelievers fight in obedience to Shaytan. Allah then encourages the believers to fight His enemies,
فَقَـتِلُواْ أَوْلِيَاءَ الشَّيْطَـنِ إِنَّ كَيْدَ الشَّيْطَـنِ كَانَ ضَعِيفاً
(So fight against the friends of Shaytan; ever feeble indeed is the plot of Shaytan).
أَلَمْ تَرَ إِلَى الَّذِينَ قِيلَ لَهُمْ كُفُّواْ أَيْدِيَكُمْ وَأَقِيمُواْ الصَّلَوةَ وَءَاتُواْ الزَّكَوةَ فَلَمَّا كُتِبَ عَلَيْهِمُ الْقِتَالُ إِذَا فَرِيقٌ مِّنْهُمْ يَخْشَوْنَ النَّاسَ كَخَشْيَةِ اللَّهِ أَوْ أَشَدَّ خَشْيَةً وَقَالُواْ رَبَّنَا لِمَ كَتَبْتَ عَلَيْنَا الْقِتَالَ لَوْلا أَخَّرْتَنَا إِلَى أَجَلٍ قَرِيبٍ قُلْ مَتَـعُ الدُّنْيَا قَلِيلٌ وَالاٌّخِرَةُ خَيْرٌ لِّمَنِ اتَّقَى وَلاَ تُظْلَمُونَ فَتِيلاً - أَيْنَمَا تَكُونُواْ يُدْرِككُّمُ الْمَوْتُ وَلَوْ كُنتُمْ فِى بُرُوجٍ مُّشَيَّدَةٍ وَإِن تُصِبْهُمْ حَسَنَةٌ يَقُولُواْ هَـذِهِ مِنْ عِندِ اللَّهِ وَإِن تُصِبْهُمْ سَيِّئَةٌ يَقُولُواْ هَـذِهِ مِنْ عِندِكَ قُلْ كُلٌّ مِّنْ عِندِ اللَّهِ فَمَا لِهَـؤُلاءِ الْقَوْمِ لاَ يَكَادُونَ يَفْقَهُونَ حَدِيثاً
Tafsir Ibn Kathir (abridged, English).