So before the Messiah was born it was enough to believe that one day He would show up and say or do something to save them ?@TokiEl
To imagine that there was no salvation for those who looked forward to the coming of the Messiah would be a very odd reading of scripture. E.g. Genesis 15:6, deferring to Abraham.
"And he believed in the LORD; and he counted it to him for righteousness"
Well He showed up alright and paid for their sins with His blood.
But have you read anywhere in the Old Testament where God state that salvation is believing in the coming of the Messiah ?
I think there are First Nations from one or more of the ten Israeli tribes.Additionally, to imagine that the message of God had not gone out to cultures wider than the Hebrews would again be incorrect. The nations immediately in contact with them would know there was something very different about the God of the Hebrews and have to make a decision on what that meant for them. There are also evidences of an awareness of a distinctly Judeo-Christian concept of God in cultures you would not expect. E.g. Native American Indians (great book btw)
But the Gospel of Jesus Christ i don't think they heard about before the age of discovery.
Now i'm not saying do not believe the Good News. But i am saying repent or you will all likewise perish.