Al-Qasas 28:86

Wama kunta tarjoo an yulqailayka alkitabu illa rahmatan min rabbikafala takoonanna thaheeran lilkafireen

And you were not expecting that the Book would be conveyed to you, but [it is] a mercy from your Lord. So do not be an assistant to the disbelievers.

You were not expecting that the Book would be sent down to you, but it was a mercy from your Lord. So, never be a supporter for the infidels.