Allah says,
ولقد مكناهم فيما إن مكناكم فيه
And indeed We had firmly established them with that wherewith We have not established you!
means, `We have granted the earlier nations wealth and offspring in the worldly life. That which We granted them, we did not give you anything similar or close to it.'
Furthermore,
وجعلنا لهم سمعا وأبصارا وأفيدة
فما أغنى عنهم سمعهم وﻻ أبصارهم وﻻ أفيدتهم من شيء
إذ كانوا يجحدون بايات الله وحاق بهم ما كانوا به يستهزوون
We also gave them hearing, vision, and hearts. But their hearing, vision, and hearts availed them nothing when they used to deny Allah's signs, and they were completely encircled by that which they used to ridicule!
meaning, they were encircled by the torment and exemplary punishment that they denied and whose occurrence they doubted.
This means, you listeners must beware of being like them lest a punishment similar to theirs strikes you in this life and the Hereafter.
Allah then says,