"O people of the Scripture (Jews and Christians): Come to a word that is just between us and you”
The religion of Islam is an upright religion that calls to the people of the book from among the Jews and the Christians, to some common ground, that commonality is what was the message of all the prophets, a word that is no rejected except by those who are astray, a word which is not exclusive to one side over another, rather they are both implicated in this word, this is to be objective this word can be broken down into the following:
1)    That we single out Allah alone for worship, and so love him and are fearful and hopeful in him.

2)    That we do not associate any partners with him, not to  a prophet or a saint nor an idol or a statue.

3)    That obedience is only for the messengers of Allah and His prophets, as they are the bringers of glad tidings for us and the Jinns and the bring us likewise a warning.

4)    That there is no obedience to the creation if that means a disobedience to the creator. By obeying other than Allah you are offering a part lordship to that thing.

By agreeing to these pure words , words that are common ground for all leaving behind partisanship, desires and falsehood, these words would then permeate into ones natural disposition and with sincerity of the heart would lead to an agreement with the Muslims:
That belief in what the last messenger bought, regarding absolute oneness of Allah, a pure and clear doctrine, guided worship, beautified transactions and interactions and a high moral, ethical and behavioral code. Moreover it will confirm the belief in the final revelation of Allah and the seal of His messengers Muhammad (pbuh), belief in a book that came as a confirmation on all the other revelatory texts, a scripture that Allah has undertaken the preservation and protection of, a book the  authenticity  of which has been proven.

Islam is therefore the religion of God as Allah says:
85. And whoever seeks a religion other than Islam, it will never be accepted of him, and in the Hereafter he will be one of the losers. (The Family of Imraan 85)

Islam in brief is the complete surrender and submission to Allah, and the belief in all of Allah’s messenger including the belief in Moses and in Jesus (peace be upon them) and in the final prophet of Allah the seal of all the prophets Muhammad.