Surah Ghafir Tafseer

ذَلِكَ بِأَنَّهُمْ كَانَت تَّأْتِيهِمْ رُسُلُهُم بِالْبَيِّنَاتِ

That was because there came to them their Messengers with clear evidences,

meaning with clear proof and definitive evidence.

فَكَفَرُوا

but they disbelieved.

means, despite all these signs, they disbelieved and rejected the Message.

فَأَخَذَهُمُ اللَّهُ

So Allah seized them.

means, He destroyed them utterly, and a similar fate awaits the disbelievers.

..

إِنَّهُ قَوِيٌّ شَدِيدُ الْعِقَابِ

Verily, He is All-Strong, Severe in punishment.

means, He is possessed of great strength and might.

شَدِيدُ الْعِقَابِ

(Severe in punishment),

means, His punishment is severe and agonizing;

we seek refuge with Allah, may He be blessed and exalted, from that