"And there will appear to them from Allah what they had not expected," meaning: they had not expected that they would be resurrected and punished.
﴿وَبَدَا لَهُمْ مِنَ اللَّهِ مَا لم يَكُونُوا يحتسبون﴾ يَعْنِي: لم يَكُونُوا يحتسبون أَنهم مبعوثون ومعذبون.