While I was in seminary, I spent some time volunteering with the youth group of a local church. A friend was the youth minister there, and he brought me in to help with events and other special goings-on. The first time my services were required was for the One Way Weekend. Essentially an extended lock-in (with the kids spending the nights with church members), we interspersed teaching time with our own version of The Price Is Right, games of Grog, and showing the next generation it is possible to sing all the lyrics and the guitar solo in "Bohemian Rhapsody." (They claimed to have never heard the song before, so that had to be corrected as a Christian duty.)
The real theme, though, came from John 14:6: "I am the way, the truth, and the life. No one comes to the Father except through me." Christ makes it crystal clear he provides the only path to salvation. There is only one way to heaven, one way to forgiveness of sins, and one way to become a new creation who will live eternally. That way is Jesus, the one God who put on flesh, died for us, and rose again.
Religious scholars sometimes try to change that message. They condemn it as exclusive (which it is) and prefer instead to be pluralist, here meaning universalist -- everyone is saved no matter what; no one goes to hell. Others seek a compromise position called inclusivism: as long as you're faithful to whichever religion and God/god(s) you choose, the real one (whichever it is) says you're okay; only those of no faith whatsoever are damned.
Pluralism and inclusivism contradict the words of Christ in John 14 (and other words by other people in other passages as well). There is only one true God: God the Father, God the Son, God the Holy Spirit. There is only one name which can save: the name of Jesus. There is only one way to salvation: the cross and atoning death of Jesus Christ.