Yes, there is no other way (John 14:6), but what would you say to the Mormon who says "all" are resurrected because of Jesus & therefore "all" are "saved?"
The Bible does say all will be resurrected. It also indicates some will be saved, and some not. Do you agree?
Note this passage: And shall come forth; they that have done good, unto the resurrection of life; and they that have done evil, unto the resurrection of damnation. (John 5:29)
Simply put, "damnation" is not a degree of "glory" or "heaven" in any way shape or form. There is a resurrection of damnation, and when you look at the original Greek it means "judgment" and "condemnation." (It doesn't mean "stopped up" like Joseph Smith said it did).
Don't keep us guessing...what is your definition of a Christian?
A Christian is one who...
...knows the only true Jesus, and His Father who sent Him (John 17:3)...and this is a relational knowledge that includes praying directly to Him and worshipping Him wholly, not just "head" knowledge in knowing "about" Him...
...is filled with the energy of the Holy Ghost, represented by the symbol of "oil" in Matthew 25:1-12...
...has received the gift of faith in Jesus Christ (Eph. 2:8-9; Rom. 6:23) as a substitute covering for his/her own sins, which Paul commonly references as being "in Christ"...
...and is not trusting in his/her own good works to save him. A Christian is one who is saved by grace before all he/she can do--not after.
[if you read John 3, John 5, John 6, and 1 John 5 carefully, you'll note that eternal life is a present tense gift and relationship with Jesus, not a spiritual school grade assigned in the afterlife].