The Basics of Eternal Salvation Through Jesus Christ
http://www.bible-knowledge.com/what-is-salvation/
As you will see in the very powerful verses I will be listing in this article – Jesus Christ, and His sacrificial death on the cross, is the central and most important fundamental, basic tenet of the Christian faith. Jesus Christ is God’s only plan of eternal salvation for the entire world.
The Bible specifically says, without any other possible interpretation, that there is only one God, one faith, one baptism, and one way to God the Father – and that is only through His Son Jesus Christ and His sacrificial death on the cross. Jesus says that He, and only He, is the way, the truth, and the life leading to God the Father and that no one comes to the Father except through Him!
From the New Testament:
“Nor is there salvation in any other, for there is no other name under heaven given among men by which we must be saved.” (Acts 4:12 )
“For there is one God and one Mediator between God and men, the Man Christ Jesus, who gave Himself a ransom for all …” (1 Timothy 2:5 )
“There is one body and one Spirit … one Lord, one faith, one baptism, one God and Father of all, who is above all, and through all, and in you all.” (Ephesians 4:4 )
Jesus said to him, “I am the way, the truth, and the life. No one comes to the Father except through Me.” (John 14:6 )
“I am the door. If anyone enters by Me, he will be saved, and will go in and find pasture … I have come that they may have life, and that they may have it more abundantly.” (John 10:9 )
Jesus said to her, “I am the resurrection and the life, he who believes in Me, though he may die, he shall live. And whoever lives and believes in Me shall never die.” (John 11:25 )
Then Jesus spoke to them again, saying, “I am the light of the world. He who follows Me shall not walk in darkness, but have the light of life.” (John 8:12 )
And Jesus said to them, “I am the bread of life. He who comes to Me shall never hunger and he who believes in Me shall never thirst.” (John 6:35 )
“I am the living bread which came down from heaven. If anyone eats of this bread, he will live forever; and the bread that I shall give is My flesh, which I shall give for the life of the world.” (John 6:51 )
“… whoever believes in Him should not perish but have eternal life. For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life.” (John 3:15-16 )
“He who believes in the Son has everlasting life; and he who does not believe the Son shall not see life, but the wrath of God abides on him.” (John 3:36 )
“Therefore I said to you that you will die in your sins; for if you do not believe that I am He, you will die in your sins.” (John 8:24 )
“Most assuredly, I say to you, he who hears My word and believes in Him who sent Me has everlasting life, and shall not come into judgment, but has passed from death to life.” (John 5:24 )
“… 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 )
“And we have seen and testify that the Father has sent the Son as Savior of the world. Whoever confesses that Jesus is the Son of God, God abides in him, and he in God.” (1 John 4:14 )
P.S. If Christians believed that other religions would do OK on their own, why do they proselytize and send missionaries to "save' and convert others?