Is the call to the oneness of Allah (tawhid) valid for the people of the Qiblah, even if they differ in the fundamentals of belief?

Question:
May Allah reward you, Honorable Shaykh. This questioner says: Is the current call valid, which states that it is necessary for Muslims to unite, even if they differ in some fundamentals, as long as they are within the circle of Islam? Because we face a single enemy?

Answer:
This is a contradiction. How can they unite when their beliefs are different? This is not possible; it is combining opposites. They will not agree except on the correct belief that united the Companions with the Messenger of Allah (peace and blessings be upon him). On what did the Companions unite? They were in the pre-Islamic age of ignorance (jahiliyyah) and were different: one worshipped the sun, one worshipped the moon, one worshipped the angels, one worshipped the jinn, one worshipped Jesus, and one worshipped trees and stones. They were at war with one another. So when they unified Allah and obeyed the Messenger of Allah (peace and blessings be upon him), and said, "There is no god but Allah," and acted upon it, they became united. So no one will unite this Ummah except what united its beginning.
As Imam Malik (may Allah have mercy on him) said: "The end of this Ummah will not be rectified except by what rectified its beginning." I wish those who hold conferences would engage in dialogue between the sects or between the scholars. Whoever is found to be with the truth would take it, and whoever erred would return from his error. I wish they would do this.
I wish they would do this; there would be benefit in that. But that they say, "Come, let us gather, and each remains on his belief," this is among the opposites that is not possible. Yes.