Luke 13:33

But because the Pharisees thought that He who was the Lord of hosts, feared the hand of Herod. He refutes this, saying, Nevertheless I must walk to day and to morrow, and the day following. When He says must, He by no means implies a necessity imposed upon Him, but rather that He walked where He liked according to the inclination of His will, until He should come to the end of the dreadful cross, the time of which Christ shows to be now drawing near, when He says, To day and to morrow.

As if He says, What think ye of My death? Behold, a little while, and it will come to pass. But by the words, To day and to morrow, are signified many days; as we also are wont to say in common conversation, "To day and to morrow such a thing takes place," not that it happens in that interval of time. And to explain more clearly the words of the Gospel, you must not understand them to be, I must walk to day and to morrow, but place a stop after to day and to morrow, then add, and walk on the day following, as frequently in reckoning we are accustomed to say, "The Lord's day and the day after, and on the third I will go out," as if by reckoning two, to denote the third. So also our Lord speaks as if calculating, I must do so to day, and so to morrow, and then afterward on the third day I must go to Jerusalem.

But because they said unto Him, Depart from hence, for Herod seeks to kill thee, speaking in Galilee where Herod reigned, He shows that not in Galilee, but in Jerusalem it had been fore-ordained that He should suffer. Hence it follows, For it can not be that a prophet perish out of Jerusalem. When thou hearest, It can not be (or it is not fitting) that a prophet should perish out of Jerusalem, think not that any violent constraint was imposed upon the Jews, but He says this seasonably with reference to their eager desire after blood; just as if any one seeing a most savage robber, should say, the road on which this robber lurks can not be without bloodshed to travellers. So also no where else but in the abode of robbers must the Lord of the prophets perish. For accustomed to the blood of His prophets, they will also kill the Lord; as it follows, O Jerusalem, Jerusalem, which killest the prophets.