Is Jesus the only way to heaven? Before attempting an answer, we must ask a prior question. Is the life of God that was poured out and perfected upon the cross strong enough and deep enough to effect the salvation of the whole world? The former question is problematic if we cannot answer the latter with a certain and emphatic ‘Yes!’
To answer ‘no’ is to imply that we see Jesus as a life raft tossed into the ocean, which must be found and utilized by a drowning person. If that were the case, then I would have trouble blaming anyone for a desire to multiply the rafts so that more and more persons might find rest in their quest to stay afloat – and that is often how the more liberal voices come across when justifying alternative religions as paths to salvation. On the other side, more conservative voices that require the unique particularity of Jesus come across as cruel in their comfort with the notion that many will drown even if they never had fair access to the limited number of rafts available.
Beginning with the latter question points to the possibility that the life, death, and resurrection of Jesus reveals to the whole world that God has made an island in the midst of the ocean; an island big enough to give rest to all the world; an island with food and water to satisfy every need and shelter to protect from every storm. If that is the case, then arguing over what brand is printed on your life preserver necessarily points your answer in the wrong direction.
Perhaps some will refuse to leave the ocean, preferring the fight for survival to the fear of the unknown. But it remains much more faithful to the Christian story to understand that Jesus is not one small life raft in an ocean full of lost and drowning souls. We may think we are doing the world a service by trying to find more boats, whether inside traditional Christian understanding or not, but God in Christ by the power of the Spirit effects a wholly different plan to end our struggles in the ocean. As Jesus was raised upon the cross, so God has raised up the dry land to save us from our drowning and make possible a new life shared in harmony with all creation. Starting with that affirmation changes the meaning and possible outcomes of the former question entirely.