So Job had an idea of an afterlife even if Judaism didn't. Jesus did not espouse "following the law." He excoriated those who mindlessly followed practices of the law and ignored the spirit behind the law. Christian belief is very specific. Rom 10:9 "... if you confess with your mouth, 'Jesus is Lord,' and believe in your heart that God raised him from the dead, you will be saved."
There was doubt in the early church, but there was never any doubt in the minds of the apostles that Jesus rose from the dead. That was (and is) the difference between Christian and Jew.
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