Then came the angel of death and slaughtered the shochet: In the time Ezra there was a failure as we learn in the Talmud: “Till Thy people pass over, O Lord.” This refers to the first entry [into Palestine in the time of Joshua]; till Thy people pass over, which thou hast purchased: this refers to their second entry (In the time of Ezra). Hence you may reason: The Israelites were as worthy of a miracle being wrought for them at the second entry as at the first, but that sin caused it [not to happen].” The point here is because of sin – that the people did not all return to Zion in the time of Ezra; many remained behind - they were not worthy of the great miracles they witnessed during the first entrance to the land. So once again the people fell into sin.