فَأَثَابَهُمُ اللّهُ بِمَا قَالُواْ

So because of what they said, Allah awarded them...

rewarding them for embracing the faith and recognizing and believing in the truth. 
 
جَنَّاتٍ تَجْرِي مِن تَحْتِهَا الَانْهَارُ خَالِدِينَ فِيهَا

Gardens under which rivers flow (in Paradise), they will abide therein forever.

and they will never be removed from it, for they will dwell and remain in it forever and ever,
 
وَذَلِكَ جَزَاء الْمُحْسِنِينَ
 
 

Such is the reward of good-doers.

who follow the truth and obey it wherever, whenever and with whomever they find it.

Allah then describes the condition of the miserable