ERROR: Theories of Christ's Return after Jesus' generation passed away

Jesus taught His Return before His generation passed away, LINK.

Jesus' Apostles understood, expected & taught Christ's Return before their generation passed away, LINK.

Though "neither the day nor the hour," (date & time), of Christ's Return was known by Jesus & His Apostles, they did plainly understand which generation would see it, their generation, LINK. Those who saw the Master go away were to be the very ones to see Him come back, as all the parables of a returning master describe, LINK.