Regarding Jesus’ death, the bible gives an account of Jesus being captured and handed over to the Romans to be crucified like a common criminal. This method of crucifixion seemed to be a standard Roman execution procedure, as two criminals were also crucified next to Jesus.

However, it seems Christianity has woven in a “ritualistic” meaning to Jesus’ execution, in holding that the crucifixion was to take away the sins of the whole world. Hence, the idea that one can be “saved” by believing that Jesus died for their sins.
Some Christians even compare Jesus execution to the ritual sin-sacrifice of unblemished animals in the Old Testament to conclude that Jesus, being without sin, was the unblemished “sacrifice” to take away the sins of the world.

On one hand, the bibles account of the crucifixion shows that it was a standard Roman execution… the result of people who wanted Jesus dead.
And on the other hand, Christian doctrine maintains that Jesus’ execution was a sin-sacrifice, which removes ones sins if they just believe that Jesus died for their sins.

Christian doctrine of the sin sacrifice is not at all rooted in the biblical account of Jesus crucifixion, because at no point did Jesus, (whether before his arrest/during his trial/ on the cross) ever declare he was going to be crucified for the sins of people, and that all who believe so will be “saved”. So the idea that he was a sin sacrifice seems to be a later insertion, much after Jesus execution. In other words, there is no connect between what Christians believe about Jesus’ sin-sacrifice on the cross and the bible account of the crucifixion. 

I’ve also noticed that the verses used to support this idea of Jesus’ sin sacrifice are mainly from sources other than Jesus himself. So, are christians risking taking someone elses word as the truth, just because its bound in the bible and ignoring the fact that Jesus never said anything that even remotely resembles anything about the doctrine of the sin sacrifice.?