"That is the extent of their knowledge." That is, their knowledge has not reached [the reality of] the Hereafter.
﴿ذَلِكَ مَبْلَغُهُم مِّنَ الْعِلْمِ﴾ أَي: إِن علمهمْ لم يبلغ الْآخِرَة.
