Surah Zumar verse 3:
Unquestionably, for Allah is the pure religion. And those who take protectors besides Him [say], "We only worship them that they may bring us nearer to Allah in position." Indeed, Allah will judge between them concerning that over which they differ. Indeed, Allah does not guide he who is a liar and [confirmed] disbeliever.
Surah Anbiya verse 66:
He said, "Then do you worship instead of Allah that which does not benefit you at all or harm you?
Surah Nisa, verse 48:
Indeed, Allah does not forgive association with Him, but He forgives what is less than that for whom He wills. And he who associates others with Allah has certainly fabricated a tremendous sin.
Surah Hajj, verse 73:
O people, an example is presented, so listen to it. Indeed, those you invoke besides Allah will never create [as much as] a fly, even if they gathered together for that purpose. And if the fly should steal away from them a [tiny] thing, they could not recover it from him. Weak are the pursuer and pursued.