Word by Word Analysis

لِّئَلَّا يَعْلَمَ أَهْلُ ٱلْكِتَـٰبِ أَلَّا يَقْدِرُونَ عَلَىٰ شَىْءٍ مِّن فَضْلِ ٱللَّهِ ۙ وَأَنَّ ٱلْفَضْلَ بِيَدِ ٱللَّهِ يُؤْتِيهِ مَن يَشَآءُ ۚ وَٱللَّهُ ذُو ٱلْفَضْلِ ٱلْعَظِيمِ 29

[This is] so that the People of the Scripture may know that they are not able [to obtain] anything from the bounty of Allāh and that [all] bounty is in the hand of Allāh; He gives it to whom He wills. And Allāh is the possessor of great bounty.