SURAH AL-E-IMRAN: 152-153

TRANSLATION:

[3:152]
Allah has surely fulfilled His promise to you when you, with His will, were killing them off, until you showed weakness and disputed in the matter and disobeyed after He had shown you what you liked. {49} Among you there were some who were seeking the mundane, and among you there were others who were seeking the Hereafter. After that, He reversed your position against them, so that He may test you. Of course, He has forgiven you. Allah is All-Gracious to the believers.

[3:153]
When you were going away, not even turning to look at anyone, and the Messenger was calling you from behind you. He awarded you sorrow for sorrow, so that you should not grieve (in future) {50} over what you lost, or for what you suffered. Allah is All-Aware of what you do. 

INTERPRETATION:

 {49} The term “favourite things” means spoils of war which was the reason why most archers had left the hillock on which they had been posted.

{50} Meaning events like this will bring you resilience and when you encounter a hardship next time you will be more likely to endure and persevere against it, rather than remain anxious and worried.