The Ranks - 61:14
"O you who believe, be supporters of Allah. Just as Jesus, son of Mary, asked his disciples, "Who will be my supporters in the way of Allah?"His disciples said, "We are the supporters of Allah."A group of the Children of Israel believed and a group disbelieved. We supported the believers against their enemies; they prevailed."
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.