for which there is no return," meaning the Day of Resurrection. That is, no one can turn it back after Allah has decreed it and set it as a fixed time and appointed term.
"And there will be for you no refuge," meaning: any helper.
لَا مَرَدَّ لَهُ﴾ يَوْم الْقِيَامَة , أَي: لَا يردهُ أحدٌ بعد مَا حكم الله بِهِ وَجعله أَََجَلًا ووقتا.
﴿وَمَا لَكُم مِّن نَّكِيرٍ﴾ أَي: نصير
