هَـٰذَا ذِكْرُ مَن مَّعِيَ وَذِكْرُ مَن قَبْلِي (Here is the Message for those with me and the Message for those before me. - 21: 24) One explanation of this verse on which the translation is based is that ذِکر means Message and "Message for those with me" refers to Qur'an, while "the Message for those before me" refers to Torah, Injil (Evangel) and Zabur (Psalms), the earlier divine books. According to this interpretation, the meaning of the verse is that neither the Qur'an (which is the Book for the Holy Prophet ﷺ and his followers) nor the older books contain anything to suggest worship of anyone else but Allah. Despite the fact that the texts of Torah and Injil (Evangel) have been altered, it is not suggested in either of them that Allah has partners with whom he shares His authority. Another explanation of the verse is given in Al-Bahr ul-Muhit according to which the word (dhikr) means here "description", and the sense is that this Qur'an is a description for the people who were in the days of the Holy Prophet ﷺ which describes for them the rules of Shari'ah and invites them to the correct way of life. At the same time it is a description of those who were before the Holy Prophet ﷺ because it keeps alive the stories and the traditions of people long gone by.
(Or have they taken for worship gods besides Him Say:) -- O Muhammad --
(Bring your proof.) your evidence for what you are saying.
(This is the Reminder for those with me) means, the Qur'an.
(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:
(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:
(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
(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.