at what moment in history did belief in Jesus become a prerequisite for salvation?

Great question.

Christianity in the USA today only requires people to "acknowledge Jesus as their saviour and welcome him into their hearts" or something similar.

Nothing like the christianity of the early centuries. When did it change? why is there so much disagreement of salvation by faith/faith & works/works alone/rituals of baptism etc.?

Salvation is based on the concept of substitutionary atonement, first developed by St. Augustine early in the 5th century.

Salvation came when Christ walked the earth, but the Born again expeince which is the completeness of salvation came on the day of pentacost, Because, If Jesus did not raise from the dead we are still in our sins, So the true church began on the day of pentacost. Read Acts 2:47 The last p[art of the verse, this is the day of pentacost, And the Lord added to the church daily such as should be saved.

When Jesus walked and taught. Remember in Luke when He arrived at Jerusalem on the donkey for His last week on earth? As He approached the city He wept, and said as a matter of prophecy that because of the people's unbelief...because they failed to recognize the time of their visitation (recognizing that Christ was God) the city would be destroyed by encircling armies. Which it was in 70 AD by the Roman army.

Please go read through the Book of Luke Chapter 19:41-44 to see this story. It is only a few short verses but it tells an amazing story. What Jesus says will happen....actually did come to pass some 40 years after His crucifixion precisely as He said it would. Read historical accounts and the writing of Josephus to see how Jerusalem actually was encircled and destroyed.

Once a person has come to the knowledge that Jesus is the savior. Denial ensures destruction, faith saves. If youre looking for a specific Scriptural point of origin it would probably have to be Peters confession of faith in Mark. That is the earliest account we have that Jesus made his claim to fame in plain words.

Since Constantine said that Christians would no longer be prosecuted....right then when Christians got some power, the world began to fall apart...now you seemingly can't go to Heaven if you're a good decent person who does good things because it's the right thing to do, now you have to believe in something that apparently won't show itself conclusively to this world, just to get in an afterlife...well, I have a very archaic and rude hand gesture for the God that apparently thinks that believing in Him is more important than being a good person, which means in the most fundamental way is that even Hitler, who believed in God, would go to Heaven, and that Gandhi, would go to Hell...that's what I'm reading from that view...just my take on it...and hope I helped somehow....

Technically, it was from the words of Genesis 3:15 .....onward.

However, that was a comment for the future.

Generally it was at Christ's death and resurrection.

That means a 3 day period.

It was the moment when you - or any other individual - first heard enough about God as revealed in Jesus Christ to make up your own mind.

Whether your decision was explicit or not, the way you live your life will show what that decision was.

That is one of the teachings of Jesus Christ when He bacame man If you have belief in God,believe His teachings.

jtm

MY vote would be Genesis 3:15, from the BEGINNING.

from the begining in Genesis 3:15 about 6000 years ago.