"So God gave them" i.e., He granted them "the reward of this world and the best reward of the Hereafter." As for the reward of this world, it is victory over their enemy, and as for the reward of the Hereafter, it is Paradise.
Muhammad said: "And their saying was not" can be read both in the nominative (rafa') and the accusative (nasb). Whoever reads it in the nominative makes the predicate of "kana" (was) that which comes after "illa" (except). In speech, it is more frequent that the subject is what comes after "illa," so the meaning would be: "And their saying was nothing but their seeking forgiveness."
﴿فآتاهم الله﴾ أَعْطَاهُم ﴿ثَوَابَ الدُّنْيَا وَحُسْنَ ثَوَابِ الْآخِرَة﴾ أما ثَوَاب الدُّنْيَا: فالنصر على عدوهم، وَأما ثَوَاب الْآخِرَة: فالجنة.
قَالَ مُحَمَّد: تقْرَأ ﴿وَمَا كَانَ قَوْلهم﴾ بِالرَّفْع وَالنّصب؛ فَمن قَرَأَ بِالرَّفْع: جعل خبر ((كَانَ)) مَا بعد ((إِلَّا)) وَالْأَكْثَر فِي الْكَلَام أَن يكون الِاسْم هُوَ مَا بعد ((إِلَّا)) فَيكون الْمَعْنى: وَمَا كَانَ قَوْلهم إِلَّا استغفارهم. [آيَة ١٤٩ - ١٥١]
