Word by Word Analysis

وَلَئِنْ أَصَـٰبَكُمْ فَضْلٌ مِّنَ ٱللَّهِ لَيَقُولَنَّ كَأَن لَّمْ تَكُنۢ بَيْنَكُمْ وَبَيْنَهُۥ مَوَدَّةٌ يَـٰلَيْتَنِى كُنتُ مَعَهُمْ فَأَفُوزَ فَوْزًا عَظِيمًا 73

But if bounty comes to you from Allāh, he will surely say, as if [i.e., showing that] there had never been between you and him any affection, "Oh, I wish I had been with them so I could have attained a great attainment."