Al-Anbya 21:25

Or have they taken for worship gods besides Him Say: "Bring your proof. This is the Reminder for those with me and the Reminder for those before me." But most of them know not the Truth, so they are averse (24)And We did not send any Messenger before you but We revealed to him (saying): "There is no God but I, so worship Me. (25)

أَمِ اتَّخَذُوا مِن دُونِهِ آلِهَةً ۖ قُلْ

(Or have they taken for worship gods besides Him? Say:) – O Muhammad –

هَاتُوا بُرْهَانَكُمْ

(Bring your proof.) your evidence for what you are saying.

هَٰذَا ذِكْرُ مَن مَّعِيَ

(This is the Reminder for those with me) means, the Qur'an.

وَذِكْرُ مَن قَبْلِي

(and the Reminder for those before me) means, the previous Books, unlike what you claim. Each Book was revealed to each Prophet who was sent with the message that there is no god except Allah, but you idolators do not recognize the truth, so you turn away from it. Allah says:

وَمَا أَرْسَلْنَا مِن قَبْلِكَ مِن رَّسُولٍ إِلَّا نُوحِي إِلَيْهِ أَنَّهُ لَا إِلَٰهَ إِلَّا أَنَا فَاعْبُدُونِ

(And We did not send any Messenger before you but We revealed to him (saying): "There is no god but I...") This is like the Ayat:

وَاسْأَلْ مَنْ أَرْسَلْنَا مِن قَبْلِكَ مِن رُّسُلِنَا أَجَعَلْنَا مِن دُونِ الرَّحْمَٰنِ آلِهَةً يُعْبَدُونَ

(And ask those of Our Messengers whom We sent before you: "Did We ever appoint gods to be worshipped besides the Most Gracious?")(43:45)

وَلَقَدْ بَعَثْنَا فِي كُلِّ أُمَّةٍ رَّسُولًا أَنِ اعْبُدُوا اللَّهَ وَاجْتَنِبُوا الطَّاغُوتَ

(And verily, We have sent among every Ummah a Messenger (proclaiming): "Worship Allah, and avoid Taghut (all false deities).")(16:36)

Every Prophet who was sent by Allah called people to worship Allah Alone, with no partner or associate. The natural inclination of man (Al-Fitrah) also bears witness to that. The idolators have no proof and their dispute is of no use before their Lord; on them is wrath, and for them will be a severe torment.