It’s pretty clear in the gospel isn’t it? Jesus says, “I am the Way, the Truth and the Life. No one comes to the Father except through me.”
This sounds clear: “Jesus is the only way to God.”
When you combine this with the teaching in the third chapter of John’s gospel the message is even more stark. Jesus says to Nicodemus, “Whoever believes in him [God’s Son] is not condemned,but whoever does not believe stands condemned already because they have not believed in the name of God’s one and only Son.”