Jn 14:6, Acts 10:43, 1 Tim 2:5
The Old Testament prophesied that those who believed in Christ would have their sins forgiven. Jesus is the Christ. (Act 10:42-43)
Act 10:42 And he commanded us to preach unto the people, and to testify that it is he which was ordained of God to be the Judge of quick and dead. 43 To him give all the prophets witness, that through his name whosoever believeth in him shall receive remission of sins.
There is no salvation except Christ Jesus. (Act 4:10-12, Jn 14:6)
Act 4:10 Be it known unto you all, and to all the people of Israel, that by the name of Jesus Christ of Nazareth, whom ye crucified, whom God raised from the dead, even by him doth this man stand here before you whole. 11 This is the stone which was set at nought of you builders, which is become the head of the corner. 12 Neither is there salvation in any other: for there is none other name under heaven given among men, whereby we must be saved.
Jn 14:6 Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me.
Only Christ Jesus is the mediator between God and man. (1 Tim 2:5)
1 Tim 2:5 For there is one God, and one mediator between God and men, the man Christ Jesus;