The Companies - 39:15 "Say, "You serve whomsoever you wish besides Him."Say, "The real losers are those who make themselves and their families lose on the Day of the Hereafter."This is the obvious loss"
Related:
The Cow/2:145 Even if you bring to those who have been given the Book all kinds of signs (miracles), they will still not turn towards your Qiblah. Nor will you follow their qibla. Nor do they follow each other´s qibla. If you follow their pleasure after this knowledge has come to you, you will be of the wrongdoers.
The Cow/2:120 "Neither the Jews nor the Christians will be pleased with you unless you enter into their religion. Say: "The right way is the way of Allah."If you follow their desires after the knowledge that has come to you, you will find neither a friend nor a supporter to defend you against Allah."

The Cattle/6:56 "Say: "I am forbidden to serve those whom you call besides Allah."Say: "I will not follow your pleasure, otherwise I will go astray and will not find the right path."

Prophet Jonah/10:104 "Say: "O people, if you have any doubt about my religion, know that I do not serve those whom you serve besides Allah. I serve only Allah, Who took your life. I am commanded to be of the believers."

The Companies/39:11 "Say, "I have been commanded to serve Allah alone in worshipping Him."
The Companies/39:12 And I have been commanded to be a Muslim to the highest degree.
The Companies/39:13 "Say, "If I disobey my Lord, I fear the punishment of the Great Day."
The Companies/39:14 "Say, "I dedicate my religion to Allah alone and serve Him."
The Companies/39:15 "Say, "You serve whomsoever you wish besides Him."Say, "The real losers are those who make themselves and their families lose on the Day of the Hereafter."This is the obvious loss"

The Forgiver/40:66 "Say, "After clear proofs have come to me, I am forbidden from serving those whom you call upon besides Allah, and I am commanded to submit to the Lord of the Universes."

The Disbelievers/109:3 And you do not serve that which I serve.
The Disbelievers/109:4 I will never serve those whom you serve.
The Disbelievers/109:5 Nor will you serve that which I serve.
The Disbelievers/109:6 Your religion is for you and my religion is for me.