He has seen the terrible destruction of Jerusalem in 587 B.C. where many of the people were slaughtered by the Babylonians and the survivors dragged off to Babylon. However he is shown that after one generation the Jews will return to Jerusalem and build up the city. Then he is shown the ministry of Jesus among the Jews and how he would be scourged and crucified. He had an angel explain to him the need for this redemptive atoning sacrifice that Jesus would provide.