"Each one," he means: of those who were destroyed from the past nations.
"Except they denied the messengers, so My penalty became due," he means: His punishment of them through torment.
﴿إِن كُلّ﴾ يَعْنِي: من أَهْلَكَ مِمَّن (مضى) من الْأُمَم السالفة.
﴿إِلا كَذَّبَ الرُّسُل فَحق عِقَاب﴾ يَعْنِي: عُقُوبَته إيَّاهُم بِالْعَذَابِ
