The Wisdom behind the hardships of the Muslims at Uhud
The subject of verse 165, أَوَلَمَّا أَصَابَتْكُم translated as, And how is it that, when you suffered a hardship the twice of which you had inflicted upon them...° has appeared in several previous verses. Here, it comes for the sake of emphasis and further clarification because Muslims were very much disturbed as a result of this incident, so much so that some of them could not resist wondering why should they be suffering in that manner (أَنَّىٰ هَـٰذَا) while they were in the company of the Holy Prophet ﷺ ، doing Jihad.
In this verse, Muslims are being reminded that the hardship they were facing that day was only half of what they had already inflicted earlier at the battle of Badr, for seventy Muslims were martyred at اُحُد Uhud while seventy disbelievers were killed at بدر Badr and seventy others from them were taken prisoners by Muslims. The purpose behind this reminder is that Muslims should think positively in their present state of depression in view of the fact that they had already won a battle, inflicting a loss on the enemy twice as much as they had themselves suffered at their hands. Now, a winner-like this need not surrender to sorrow and grief in the event defeat comes once, or less.
Secondly, and primarily too, the purpose of saying, قُلْ هُوَ مِنْ عِندِ أَنفُسِكُمْ 'This is from your ownselves' at the end of this verse, is to tell Muslims that the hardship they have faced is not because the enemy is stronger or his forces overwhelming, but all that has been caused by some of their own shortcomings, that is, they fell short in obeying the command of the Holy Prophet ﷺ .