“Therefore, let not the one who believes not therein (i.e. in the Day of Resurrection) but follows his own lusts, divert you therefrom, lest you perish.”
This Ayah is a stern reminder to not let absolutely anyone who does not believe in the Day of Judgment get in our head and obstruct us from remembering it. Notice that this Ayah is not saying that these people will make us disbelieve in the Hour. No, it’s not about disbelieving, because we Muslims believe in the Hour. But this Ayah talks about the diversion from remembering the Hour.
Because when we hang out with the wrong kind of people, we stop remembering it. We stop thinking about it. And the more we hang around with them, the more we get so turned off from remembering it, to the point that when someone tries to advise us, we might say, “Can we talk about something less depressing please?”
This is important to take heed of. When someone stops thinking about the Hour, they stop thinking of the consequences of their actions. And when that happens, they will end up doing whatever they desire, whatever urge they have, even though that desire is completely impermissible.
This Ayah reminds us that if we allow such a thing to happen, it will bring us to our own downfall.