Writing in the Apologetics Study Bible for Students, Brett Kunkle writes:

That Jesus is the only way to God may be the most controversial claim of Christianity, so we had better have good reason for making it. I think we do.

What does Jesus say? We don’t want to claim something about Jesus that he wouldn’t claim of himself. If the Gospels are historically reliable (we have overwhelming evidence they are), then we have Jesus’s own words and by examining them we discover that he claims to be the only way to God. In John 14:6, Jesus says, “I am the way, the truth, and the life. No one comes to the Father except through me.” This doesn’t leave much room for debate. Indeed, Jesus says whoever rejects him rejects God, for God sent him (Lk 10:16). So according to Jesus, there’s no other path to God. If you wish to follow Jesus, you must accept the claims he made about himself.

Is Jesus special? Those who claim that all religions are basically the same haven’t studied them closely, for the religions often contradict one another. Hinduism says God is an impersonal force while Christianity says God is a personal Being. Both cannot be true. Also, Jesus is unique among religious figures. His disciples said he is God (Jn 1:1; Php 2:5–7) because Jesus himself said so (Mk 14:61–64; Jn 10:30–34). No other founder of a major world religion claimed to be God. Now, Jesus was either right or wrong to make his claim, and he provided a standard to verify it. He said his resurrection from the dead would be confirmation (Mt 12:38–42; Mk 14:28). Siddhartha, the founder of Buddhism, is still in his grave. Muhammad, the founder of Islam, is still dead. But not Jesus. He conquered death and thus provided the ultimate evidence for the truth of his unique claims.

Why is Jesus the only way? We are conditioned by our culture to think of religion as a personal preference. We are told, “You’ve got your religion and I’ve got mine.” To claim Jesus is the only way to God seems like claiming chocolate ice cream is the one true flavor. However, religious truth does not come down merely to differences in preference. Instead, we should think of religion the same way we think of medicine. Each religion recognizes the world is sick and offers a diagnosis. In addition, each religion offers a means of being cured. Just like when our doctors must choose the right medicine to cure us, we must choose the religion that offers the genuine cure to our sickness. In John 8:24, Jesus says “if you do not believe that I am he, you will die in your sins.” Jesus offers both diagnosis and cure. Sin is the disease we’re all infected with and Jesus is the one true cure. So, why is Jesus the only way? Because Jesus is the only medicine that can cure the spiritual disease—sin—that is killing us.