﴿ ۞ إِذْ تُصْعِدُونَ وَلَا تَلْوُۥنَ عَلَىٰٓ أَحَدٍۢ وَٱلرَّسُولُ يَدْعُوكُمْ فِىٓ أُخْرَىٰكُمْ فَأَثَٰبَكُمْ غَمًّۢا بِغَمٍّۢ لِّكَيْلَا تَحْزَنُوا۟ عَلَىٰ مَا فَاتَكُمْ وَلَا مَآ أَصَٰبَكُمْ ۗ وَٱللَّهُ خَبِيرٌۢ بِمَا تَعْمَلُونَ ﴾

“[Remember the time] when you fled, paying no heed to anyone, while at your rear the Apostle was calling out to you - wherefore He requited you with woe in return for [the Apostle's] woe, so that you should not grieve [merely] over what had escaped you, nor over what had befallen you: for God is aware of all that you do.”

so He rewarded you with grief for grief, that is, He turned you away from them and rewarded you with grief because of a grief that befell God's Messenger from your part when you disobeyed him and lost heart and quarreled. Or [it means] grief after grief, doubled, so that you might be trained to be patient and to remain firm in adversity, and so that you might become accustomed to seeing power, victory and spoils and all things as being from God and not from your own souls, so that you might not grieve for what eluded you, of shares and benefits, neither for what befell you, of grief and harm.