From a Jewish perspective there are only two major groupings in the world, Jews and Gentiles, (Non-Jews). The non-Jews obviously include all peoples of the world who do not follow Judaism. Among these are to be found many and various “beliefs” including Christianity, Islam, Hinduism, Buddhism, Bahai, Taoism and several other isms. Interestingly, in the Quran, Islam’s holy book, there are three categories mentioned: Muslims, the People of the Book (the Jews), and idol worshipers, essentially the same as the Jewish categories except that now they add themselves as a new category.
It is interesting that Christianity is a separate group here, for I personally do not see Christianity as separate from its Judaic roots. Christ’s purpose was NOT to start a new religion, but rather that these Anointed Ones (christianous in Acts 11:26) were to be the proper fulfilment of Judaism for that time.
Hear what the Pharisee Paul says by the spirit:
Rom. 11:11-16 ¶ I say then, they (i.e. the Jews) did not stumble so as to fall, did they? May it never be! But by their transgression salvation has come to the Gentiles, to make them jealous. Now if their transgression is riches for the world and their failure is riches for the Gentiles, how much more will their fulfillment be! But I am speaking to you who are Gentiles. Inasmuch then as I am an apostle of Gentiles, I magnify my ministry, if somehow I might move to jealousy my fellow countrymen and save some of them. For if their rejection is the reconciliation of the world, what will their acceptance be but life from the dead? If the first piece of dough is holy, the lump is also; and if the root is holy, the branches are too.
Rom. 11:17-24 ¶ But if some of the branches were broken off, and you, being a wild olive, were grafted in among them and became partaker with them of the rich root of the olive tree, do not be arrogant toward the branches; but if you are arrogant, remember that it is not you who supports the root, but the root supports you. You will say then, “Branches were broken off so that I might be grafted in.” Quite right, they were broken off for their unbelief, but you stand by your belief. Do not be conceited, but fear; for if God did not spare the natural branches, He will not spare you, either. Behold then the kindness and severity of God; to those who fell, severity, but to you, God’s kindness, if you continue in His kindness; otherwise you also will be cut off. And they also, if they do not continue in their unbelief, will be grafted in, for God is able to graft them in again. For if you were cut off from what is by nature a wild olive tree, and were grafted contrary to nature into a cultivated olive tree, how much more will these who are the natural branches be grafted into their own olive tree?
Rom. 11:25 ¶ For I do not want you, brethren, to be uninformed of this mystery — so that you will not be wise in your own estimation — that a partial hardening has happened to Israel until the fullness of the Gentiles has come in…