Permission to fight; this is the first Ayah of Jihad

Allah said:

أُذِنَ لِلَّذِينَ يُقَاتَلُونَ بِأَنَّهُمْ ظُلِمُوا وَإِنَّ اللَّهَ عَلَى نَصْرِهِمْ لَقَدِيرٌ ﴿٣٩﴾

Permission (to fight) is given to those (believers) who are fought against, because they have been wronged; and surely, Allah is able to give them victory.

Al-`Awfi reported that Ibn Abbas said,

"This was revealed about Muhammad and his Companions, when they were expelled from Makkah.''

Mujahid, Ad-Dahhak and others among the Salaf, such as Ibn Abbas, Urwah bin Az-Zubayr, Zayd bin Aslam, Muqatil bin Hayan, Qatadah and others said,

"This is the first Ayah which was revealed about Jihad.''

Ibn Jarir recorded that Ibn Abbas said,

"When the Prophet was driven out of Makkah, Abu Bakr said,

`They have their Prophet. Truly, to Allah we belong and truly, to Him we shall return; surely they are doomed.'''

Ibn Abbas said, "Then Allah revealed the words:

أُذِنَ لِلَّذِينَ يُقَاتَلُونَ بِأَنَّهُمْ ظُلِمُوا وَإِنَّ اللَّهَ عَلَى نَصْرِهِمْ لَقَدِيرٌ

Permission (to fight) is given to those (believers) fought against, because they have been wronged; and surely, Allah is able to give them victory.''

Abu Bakr, may Allah be pleased with him, said, "Then I knew that there would be fighting.''

Imam Ahmad added:

"Ibn Abbas said, `This was the first Ayah to be revealed concerning fighting.'''

This was also recorded by At-Tirmidhi and An-Nasa'i in the Book of Tafsir of their Sunans.

At-Tirmidhi said: "It is a Hasan Hadith.''

.. وَإِنَّ اللَّهَ عَلَى نَصْرِهِمْ لَقَدِيرٌ

and surely, Allah is able to give them victory.

means, He is able to grant victory to His believing servants without any fighting taking place, but He wants His servants to strive their utmost in obeying Him, as He says:

فَإِذَا لَقِيتُمُ الَّذِينَ كَفَرُواْ فَضَرْبَ الرِّقَابِ حَتَّى إِذَآ أَثْخَنتُمُوهُمْ فَشُدُّواْ الْوَثَاقَ فَإِمَّا مَنًّا بَعْدُ وَإِمَّا فِدَآءً حَتَّى تَضَعَ الْحَرْبُ أَوْزَارَهَا ذَلِكَ وَلَوْ يَشَآءُ اللَّهُ لاَنْتَصَرَ مِنْهُمْ وَلَـكِن لِّيَبْلُوَ بَعْضَكُمْ بِبَعْضٍ وَالَّذِينَ قُتِلُواْ فِى سَبِيلِ اللَّهِ فَلَن يُضِلَّ أَعْمَـلَهُمْ

سَيَهْدِيهِمْ وَيُصْلِحُ بَالَهُمْ

وَيُدْخِلُهُمُ الْجَنَّةَ عَرَّفَهَا لَهُمْ

So, when you meet those who disbelieve, strike necks till when you have killed and wounded many of them, then bind a bond firmly. Thereafter either for generosity, or ransom, until war lays down its burden. Thus, but if it had been Allah's will, He Himself could certainly have punished them. But (He lets you fight) in order to test some of you with others.

But those who are killed in the way of Allah, He will never let their deeds be lost. He will guide them and set right their state. And admit them to Paradise which He has made known to them. (47:4-6)

قَـتِلُوهُمْ يُعَذِّبْهُمُ اللَّهُ بِأَيْدِيكُمْ وَيُخْزِهِمْ وَيَنْصُرْكُمْ عَلَيْهِمْ وَيَشْفِ صُدُورَ قَوْمٍ مُّؤْمِنِينَ

وَيُذْهِبْ غَيْظَ قُلُوبِهِمْ وَيَتُوبُ اللَّهُ عَلَى مَن يَشَآءُ وَاللَّهُ عَلِيمٌ حَكِيمٌ

Fight against them so that Allah will punish them by your hands, and disgrace them, and give you victory over them, and heal the breasts of a believing people, and remove the anger of their (believers') hearts. Allah accepts the repentance of whom He wills. Allah is All-Knowing, All-Wise. (9:14-15)

وَلَنَبْلُوَنَّكُمْ حَتَّى نَعْلَمَ الْمُجَـهِدِينَ مِنكُمْ وَالصَّـبِرِينَ وَنَبْلُوَ أَخْبَـرَكُمْ

And surely, We shall try you till We test those who strive hard and the patient, and We shall test your facts. (47:31).

And there are many similar Ayat.

Ibn Abbas commented on the Ayah, وَإِنَّ اللَّهَ عَلَى نَصْرِهِمْ لَقَدِيرٌ (and surely, Allah is able to give them (believers) victory),

"And this is what He did.''

Allah prescribed Jihad at an appropriate time, because when they were in Makkah, the idolators outnumbered them by more than ten to one. Were they to engage in fighting at that time, the results would have been disastrous. When the idolators went to extremes to persecute Muslims, to expel the Prophet and resolving to kill him; when they sent his Companions into exile here and there, so that some went to Ethiopia and others went to Al-Madinah; when they settled in Al-Madinah and the Messenger of Allah joined them there, and they gathered around him and lent him their support, and they had a place where Islam prevailed, and a stronghold to which they could retreat; then Allah prescribed Jihad against the enemy, and this was the first Ayah to be revealed for it.