GOD sent the mashiach (messiahs) like the prophets to correct the Priesthood's errors. Jesus wasn't the only messiah but one in a long list of prophets who were sent by GOD to correct the errors of the Temple cult. Jesus', James', and John's appearances were very necessary and gave us a glimpse of GOD that the bogus laws written within the Torah were preventing us from seeing clearly. The sacrificial laws were little more than self-serving. Jesus and James and John showed us a GOD worth following.