Again and again, Scripture stresses that Jesus Christ is the only hope of salvation for the world. "For there is one God and one Mediator between God and men, the Man Christ Jesus" (1 Timothy 2:5). Only Christ can atone for sin, and therefore only Christ can provide salvation. "And this is the testimony: that God has given us eternal life, and this life is in His Son. He who has the Son has life; he who does not have the Son of God does not have life" (1 John 5:11-12).
Those truths are antithetical to the central tenet of postmodernism. They make exclusive, universal truth claims, declaring Christ the only true way to heaven and all other belief-systems erroneous. That is what Scripture teaches. It is what the true church has proclaimed throughout her history. It is the message of Christianity. And it simply cannot be adjusted to accommodate postmodern sensitivities.
Source: Jesus: The Only Way to Heaven - Jul 15, 2005 - Grace to You with John MacArthur