This great victory was achieved by Muslims in the background which was initially full of dismay and hopelessness. So, when they returned from the battlefield, they started talking about it. The Companions ؓ got busy relating their deeds on the battlefield. Revealed thereupon was this verse: فَلَمْ تَقْتُلُوهُمْ وَلَـٰكِنَّ اللَّـهَ قَتَلَهُمْ (So, you did not kill them, but Allah killed them -17) through which they were instructed not to wax proud over their effort and deed, for that which happened there was not simply the outcome of their personal effort and deed. In fact, it was purely and simply the fruit of the help and support given by Allah Ta` ala - and the enemies killed at their hands were not really killed by them, rather, they were killed by Allah Ta` ala.

Similarly, addressing the Holy Prophet ﷺ , it was said: وَمَا رَ‌مَيْتَ إِذْ رَ‌مَيْتَ وَلَـٰكِنَّ اللَّـهَ رَ‌مَىٰ (And you did not throw when you threw, but Allah did throw). It means that the specific outcome of the act of throwing, whereby it would reach the eyes of every fighting man in the enemy force and frighten them all, was not the direct effect of 'his' throwing. It was, in fact, the perfect power of Allah Ta’ ala which generated the format of this situation. To quote Rumi for a chic poetic explanation:

ما رمیت اذ رمیت گفت حق کا رما برکارھا دارد سبق

'And you did not throw when you did,' said Allah,

'Our Act precedes all other acts.'

Certainly valuable for Muslims - more valuable than their victory in Jihad - was this instruction which disengaged their minds from means and tied it up with the master-provider of all means, and through it, saved them from falling into the trap of pride and arrogance which generally intoxicates victorious nations. After that it was said that victory and defeat are subservient to the command of Allah and that His support is with those who are obedient: وَلِيُبْلِيَ الْمُؤْمِنِينَ مِنْهُ بَلَاءً حَسَنًا (so that He may bless the believers with a good favour). It means that Allah blessed the believers with this great victory in order to give them the best of return for their obedience and struggle. The literal meaning of the word: بَلَاءً (bala' ) is test or trial. As for the test taken by Allah Ta` ala, it sometimes comes when someone is put to distress or hardship - and there are occasions when this is done by giving someone comfort and wealth. Here, the name of hasan حَسَن (good) bala' (trial) has been given to a test which is taken by giving comfort, wealth, support and victory to find out if people who are so blessed take it to be a favour from Allah and are grateful for it, or take it to be the outcome of their personal excellence, become proud and arrogant and undo what they did - because, there is no room for pride from anyone before Allah Ta` ala.