In coran you will found deferent versses ..
*and each verse can explain by another and this ayat have another which can make you understand how Allah tells us about the disbelievers
You found ayat tells you :
8 ) Then is one to whom the evil of his deed has been made attractive so he considers it good [like one rightly guided]? For indeed, Allah sends astray whom He wills and guides whom He wills. So do not let yourself perish over them in regret. Indeed, Allah is Knowing of what they do.
In this ayah Allah tells the prophet Muhammed pace be upon him to don't kill himself by thinking of theme but in other ayat Allah explain
*( 27 ) And those who disbelieved say, "Why has a sign not been sent down to him from his Lord?" Say, [O Muhammad], "Indeed, Allah leaves astray whom He wills and guides to Himself whoever turns back [to Him] -
Then he tell him about the disbelievers
*108 )Those are the ones over whose hearts and hearing and vision Allah has sealed, and it is those who are the heedless.
Then we can found the reason in other versses
3 ) That is because they believed, and then they disbelieved; so their hearts were sealed over, and they do not understand. 63:3
*35 )Those who dispute concerning the signs of Allah without an authority having come to them - great is hatred [of them] in the sight of Allah and in the sight of those who have believed. Thus does Allah seal over every heart [belonging to] an arrogant tyrant. 40:35
*100 )Has it not become clear to those who inherited the earth after its [previous] people that if We willed, We could afflict them for their sins? But We seal over their hearts so they do not hear.7:100
155 )And [We cursed them] for their breaking of the covenant and their disbelief in the signs of Allah and their killing of the prophets without right and their saying, "Our hearts are wrapped". Rather, Allah has sealed them because of their disbelief, so they believe not, except for a few.
156 ) And [We cursed them] for their disbelief and their saying against Mary a great slander,
157 )And [for] their saying, "Indeed, we have killed the Messiah, Jesus, the son of Mary, the messenger of Allah." And they did not kill him, nor did they crucify him; but [another] was made to resemble him to them. And indeed, those who differ over it are in doubt about it. They have no knowledge of it except the following of assumption. And they did not kill him, for certain.
158 )Rather, Allah raised him to Himself. And ever is Allah Exalted in Might and Wise.
So .. we can understand that when Allah tell the prophet about the disbelievers in this ayah we can found in other versses why
*afflicting them for their sins
Allah guides to Himself whoever turns back [to Him]
-He sealed their heart because they believed, and then they disbelieve " Allah show them the truth and they don't want expect the darkness
Thus does Allah seal over every heart [belonging to] an arrogant tyrant.
* May Allah guide us to understand his book and accept our deeds Amen