Prophet Abraham - 14:41
Our Lord, forgive me and my parents and those who believe on the Day of Reckoning.
Why was the father of Prophet Abraham not forgiven?
The Women/4:116
Allah does not forgive associating partners with Him (if it continues until death), but He forgives the sins below that to whom He wills. Whoever associates partners with Allah has gone astray.
The Women/4:48
Allah does not forgive associating partners with Him, but other than that He forgives to whom He wills. Whoever associates partners with Allah has committed a great insult.
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.
The Companies/39:66
So serve Allah alone and give thanks.
The Pilgrimage/22:31
Dedicate yourselves to Him alone, associating no partners with Allah. Whoever associates partners with Allah, it is as if he has fallen from the sky and has been seized by a vulture, or is being carried away by the wind in a deep fjord.
The Table Spread/5:72
"Those who say: "Allah is the Messiah, son of Mary,"have certainly disbelieved. But the Messiah said, "Children of Israel, serve Allah, my Lord and your Lord. Whoever associates partners with Allah, Allah forbids him Paradise, and his abode will be the Fire. And there will be no helper for the wrongdoers."
The Cattle/6:88
Such is the Guidance of Allah. He guides whomever He wills among His servants and/or whoever He wills to it. Had they associated partners, what they did would have been in vain.
Luqman/31:12
"We gave wisdom to Lokman: "You should give thanks to Allah."Whoever is grateful is grateful for himself, and whoever is ungrateful, surely Allah is not needy, the Most Praised."
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."