The Cow - 2:264
Believers! Do not waste your charity by insulting and persecuting, like the one who does not believe in Allah and the Last Day but gives charity to show off to the people. The example of such behavior is like a rock on which dust has accumulated so that a heavy downpour leaves it bare. They will gain nothing from what they have done. Allah does not guide the disbelieving people.
The most important criterion of belief:
The Cattle/6:82
Those who believe and do not mix their faith with wrongdoing, they deserve security and they have found the truth.
Luqman/31:13
"When Lokman advised his son, he said: "My dear son, do not associate partners with Allah; surely shirk (associating partners with God) is a great wrong."
The Companies/39:65
It has been revealed to you and those before you that if you associate partners, all that you do will be in vain and you will be of the losers.