“Your God is One God. There is none worthy of worship besides Him, the All-Merciful, the Most Merciful.” 
[al-Baqarah (2): 163]

“Allah says, ‘Do not take two gods, He is only One God. So dread Me alone.’” 
[al-Nahl (16): 51]

“Whoever calls on another god together with Allah, has no grounds for doing so at all and his reckoning is with his Lord. Truly the disbelievers have no success.” 
[al-Mu’minun (23): 117]

“Ask those We sent before you as Our Messengers: Have We ever designated any gods to be worshipped besides the All-Merciful?” 
[al-Zukhruf (43): 45]

“Some people set up equals to Allah, loving them as they should love Allah.” 
[al-Baqarah (2): 165]

“You have an excellent example in Ibrahim and those with him, when they said to their people, ‘We wash our hands of you and all that you worship apart from Allah, and we reject you. Between us and you there will be enmity and hatred for ever unless and until you have faith in Allah alone.’” 
[al-Mumtahanah (60): 4]

“Most of them do not have faith in Allah without associating others with Him.” 
[Yusuf (12): 106]

“Say, ‘To whom does the earth belong, and everyone in it, if you have any knowledge?’ They will say, ‘To Allah.’ Say, ‘So will you not pay heed?’ Say, ‘Who is the Lord of the Seven Heavens and the Lord of the Mighty Throne?’ They will say, ‘Allah.’ Say, ‘So will you not have taqwa?’ Say, ‘In whose hand is the dominion over everything, He who gives protection and from whom no protection can be given, if you have any knowledge?’ They will say, ‘Allah’s.’ Say, ‘So how have you been bewitched?’” 
[al-Mu’minun (23): 84-89]

“Or have they adopted intercessors besides Allah? Say, ‘Even though they do not control a thing and have no awareness?’ Say, ‘Intercession is entirely Allah’s affair. The kingdom of the heavens and earth is His.’…” 
[al-Zumar (39): 43-44]

“They worship, instead of Allah, what can neither harm them nor help them, saying, ‘These are our intercessors with Allah.’ Say, ‘Would you inform Allah of something about which He does not know either in the heavens or on earth?’ May He be glorified and exalted above what they associate with Him!” 
[Yunus (10): 18]

“You have come to Us all alone just as We created you at first, leaving behind you everything We bestowed on you. We do not see your intercessors accompanying you, those you claimed were partners with Allah.” 
[al-An`am (6): 94]

“Or have they adopted intercessors besides Allah? Say, ‘Even though they do not control a thing and have no awareness?’ Say, ‘Intercession is entirely Allah’s affair. The kingdom of the heavens and earth is His.’…” 
[al-Zumar (39): 43-44]

“You have come to Us all alone just as We created you at first, leaving behind you everything We bestowed on you. We do not see your intercessors accompanying you, those you claimed were partners with Allah.” 
[al-An`am (6): 94]

“Some people set up equals to Allah, loving them as they should love Allah.” 
[al-Baqarah (2): 165]

“They worship, instead of Allah, what can neither harm them nor help them, saying, ‘These are our intercessors with Allah.’ Say, ‘Would you inform Allah of something about which He does not know either in the heavens or on earth?’ May He be glorified and exalted above what they associate with Him!” 
[Yunus (10): 18]