وما نرسل المرسلين إﻻ مبشرين ومنذرين
And We send not the Messengers except as bearers of good news and warners.
before the punishment they give good news to those who believe in them and follow them, and warnings to those who reject them and oppose them.
Then Allah tells us about the disbelievers:
ويجادل الذين كفروا
But those who disbelieve, argue
بالباطل ليدحضوا به الحق
with falsehood, in order to refute the truth thereby.
they try to weaken the truth that the Messengers brought, but they cannot achieve that.
واتخذوا آياتي وما أنذروا هزوا
And they take My Ayat and that which they are warned for jest!
they take the proof, evidence and miracles sent with the Messengers to warn them, and make them fear the punishment;
هزوا
(as a jest and mockery),
and they make fun of them, which is the worst type of disbelief