Question: Do different religions and their gods all stand for the One Supreme Being, and if so, is heaven available for all their followers?
Biblical Answer: "Know therefore this day ... that the LORD [Jehovah] he is God in heaven above, and upon the earth beneath: there is none else" (Deut. 4:39).
Comments: One of the chief emphases of the Bible is that of the absolute exclusivity, the unequaled uniqueness of the only "True God", the "living God" (Jer. 10:10), revealing His name to be "Jehovah" ("LORD" in the KJV). The blatancy of error, thus, on the part of those churches and leaders who dare to make the LORD a liar and teach that all religions, all faiths are different manifestations of the one truth, is gross.
Because the LORD is the Only God, He forbids the worship of any other aside from Himself (Ex. 20:3, 34:14), whether celestial bodies (Deut. 17:3), or dead idols man-made (Hab. 2:18, 19), even the so-called "queen of heaven" (Jer. 7:18). Thus, any sacrifice offered not to the King of kings is that offered to "devils" (1 Cor. 10:20). Indeed, any other object of worship is but an idol, and "an idol", powerless and futile, is "nothing in the world" (1 Cor. 8:4). Because the name of other gods cannot in anyway refer to the God, He forbids the very mentioning of them (Ex. 23:13). Because there is One God Whose message only is to be declared and heeded (Jer. 13:10; Jn. 6:68), any supposed prophet representing another god was to be executed (Deut. 18:20), even in the event his predictions came about (Deut. 13:1-9).
Because the LORD only is omnipotent, He alone has the power of life and death, both temporal and eternal, and His decision, His verdict, whether for blessing or for judgment, is final, being irreversible by any other power (Deut. 32:39; Jn. 10:28, 29). None other than the True God, indeed, can work His marvelous works, reflective of His own unmatchable attributes (Job 5:9; Ps. 118:23; Dan. 3:29).
Amazingly, the "Only Wise God" and "Saviour" (Jude 1:12; Is. 43:11) has come on earth as the Man Lord Jesus, the Christ, to "save His people from their sins" (Mt. 1:21). As the unique God-Man ("only begotten", Jn. 3:16), Jesus is Himself "one Lord" (1 Cor. 8:6), while embodying the "one faith", and being the only Way to the "One God and Father of all" (Eph. 4:5, 6; cf. Acts 4:12; 1 Tim. 2:5) - His chosen.