This is a question each professing Christian needs to resolve for theirselves in these latter days. It is yet again a time today to test the spirits, as the Apostle John said, “Beloved, believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world” (1 John 4:1).
One of the matters which is again trying to creep into the Churches today is the false doctrine that someone or something other than Jesus Christ of Nazareth can offer Salvation. Some of that false attitude is because of various inter-faith movements springing up within Christian Churches. The inter-faith movement’s intention is to put Christianity on an equal par with all other religions of the world, and thus delegate The Lord Jesus Christ as merely a human flesh prophet, and not “Emmanuel” (Greek for ‘God with us‘ per Matthew 1:23). We know of the prophecy through Paul in 2 Thessalonians 2 that many Christian believers would fall away and become apostates in the latter days before the second coming of Christ Jesus. The inter-faith movement, called ecunemicalism, a literal joining in fellowship with other religious ideas outside God’s Word, is designed to lead up to that great falling away from Christ.
The Apostle Peter gave a Message to the rulers and religious leaders in Jerusalem in his day. It’s worth repeating for our times also…

Acts 4:10   Be it known unto you all, and to all the people of Israel, that by the name of Jesus Christ of Nazareth, Whom ye crucified, Whom God raised from the dead, even by Him doth this man stand here before you whole.
11   This is the stone which was set at nought of you builders, which is become the head of the corner.
12   Neither is there salvation in any other: for there is none other name under heaven given among men, whereby we must be saved.

     The religious system in Jerusalem during Peter’s day refused The Cornerstone Jesus Christ of Nazareth as God’s Promised Savior “Immanuel” (Isa.7; ‘God with us‘ in Hebrew). Those rulers instead had Jesus The Christ crucified upon a cross that would fulfill prophecy given through David nearly a thousand years earlier (Psalms 22). The religious leaders of Peter’s day refused the “sign” which God gave back in Isaiah’s day, which stated, “Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel“ (Isa.7:14).
The “sign” of Isaiah 7:14 was first given to a remnant of the house of David at Jerusalem for Isaiah’s time, meaning the king line Promise God made to David of always having one of his offspring established on the earthly throne would remain true (2 Sam.7:8 forward). That Promise especially involves God’s Promised Savior Jesus Christ Immanuel, Who is to eventually sit upon that throne of the house of David, on earth, ruling over all nations with a rod of iron (Gen.49:10; Rev.12:5; Rev.20; Rev.21 & 22; Ps.2). The reign of Jesus Christ of Nazareth “Emmanuel“, on earth at His second coming of the future is also our hope, if we be in Christ. There is none other Name with the “sign” given, that will bring Salvation unto Eternal Life, and it is only for those who believe. That “sign” of Isaiah 7:14 was fulfilled in Jerusalem when a virgin (Mary) conceived by The Holy Spirit, and God The Son Jesus of Nazareth was born in the flesh (Matthew 1).
So what of the ‘crept in unawares’ which are trying to distort this Truth with doctrines that all religious belief systems lead to the same God? Can the earth save us? Can belief in spirits of trees in the forest, the sea, and the creatures upon this earth save us? Can we even save our own soul unto Salvation? Absolutely not. There is only one true belief whereby we may be saved, and that is on The Promised Savior Jesus Christ of Nazareth Who shed His Blood upon the cross, and Who came in the flesh form, being without sin, as God with us on earth, Whom The Father also resurrected to the right hand of His Throne (1 Peter 3:21-22). Only God has The Power to save and can be perfect without sin (Gal.3:22). Such was our Lord Jesus The Christ on earth, and evermore.
What can we say then of the religious leaders today who invite other belief systems into our Christian Churches for the sake of solidarity and world brotherhood? Is that done in hopes that people of other faiths will come to solely believe on The Father through His Son Christ Jesus as we have? Some of them may do that, but that’s not the purpose of trying to join other belief systems with Christianity. Is the inter-faith movement of other faiths trying to join within Christianity in accordance with sound Christian Doctrine? What did the apostle Paul say about this…

2 Cor 6:14    Be ye not unequally yoked together with unbelievers: for what fellowship hath righteousness with unrighteousness? and what communion hath light with darkness?

     Christian Doctrine from our Lord Jesus through His servant Paul thus states to not be unequally yoked together with those who refuse Jesus of Nazareth as The Christ. Sadly, that also includes anyone who professes to believe in God but… not specifically on Christ Jesus as God The Savior “Emmanuel“. Just believing there is a God is not enough, for “…the devils also believe, and tremble” (James 2:19).

2 Cor 6:15   And what concord hath Christ with Belial? or what part hath he that believeth with an infidel?

     The word “Belial” is of Hebrew origin and is an epithet for Satan. There are many different belief systems in the world with some of them acknowledging there is a God, but at the same time refusing Christ Jesus as The Savior. Don’t be deceived away from the simplicity that is in Christ Jesus by falling away to those other faiths, for without The Only Savior Jesus Christ they cannot save. And if they refuse The Savior Jesus Christ, then they definitely have not believed on the same God The Father YHVH and His Son which true Christians have.

2 Cor 6:16   And what agreement hath the temple of God with idols? for ye are the temple of the living God; as God hath said, I will dwell in them, and walk in them; and I will be their God, and they shall be My people.
17   Wherefore come out from among them, and be ye separate, saith the Lord, and touch not the unclean thing; and I will receive you,
18   And will be a Father unto you, and ye shall be My sons and daughters, saith the Lord Almighty.

     Paul quoted the above three verses from passages in The Old Testament Books of Exodus, Leviticus, Jeremiah, and Ezekiel. The above is directly from God’s Ten Commandments first given through His servant Moses to His people Israel. Notice here, the apostle Paul made this a Christian Doctrine of Christ’s Church which shall be God’s future and eternal Israel, both a spiritual and a physical Israel in His Kingdom to come.
Some will then say about this, “Well, I don’t see a problem with inviting peoples of other faiths to my Christian Church.” I’m not saying Christians should totally close theirselves off from the world, and nor did Paul or our Lord Jesus teach that. This subject is about joining outside doctrines of the world, even pagan doctrines from other faith systems, in with Christian Doctrine, and still trying to call it Christianity. Our Heavenly Father had a word for those type of places that do that; He used the Hebrew word Beth-aven, which means a house of vanity (Hosea 10). Let the Bethavens go on and deny God’s Holy Writ and try to supplant It with their own truth. But those who remain true to Christ Jesus are not to be swayed by them. Let them say our belief on The Father and The Son is outdated, backward, of the dark ages, etc. In time The Savior Jesus Christ will end their murmurings against true Christians who refuse to fall away to the antichrist/false messiah which the world religious leaders are preparing all nations to worship (Rev.13:11 forward)

Peace be unto you in Christ Jesus,
Dave Ramey