Luke 20:19

It became indeed the rulers of the Jews, perceiving that the parable was spoken of them, to depart from evil, having been thus as it were warned concerning the future. But little mindful of this, they rather gather a fresh occasion for their crimes. The commandment of the Law restrained them not, which says, The innocent and righteous men thou shalt not slay, (Exod. 23:7.) but the fear of the people checked their wicked purpose. For they set the fear of man before the reverence of God. The reason of this purpose is given, for they perceived that he spoke this parable against them. For they seemed to be trifling, yet were in earnest, forgetful of God, who says, Who is this that hideth his counsel from me? (Job 42:3.) For they come to Christ the Saviour of all, as though He were a common man, as it follows, that they might take him in his speech.

And so by seeking to slay Him, they proved the truth of what He had said in the parable. For He Himself is the Heir, whose unjust death He said was to be punished. They are the wicked husbandmen who sought to kill the Son of God. This also is daily committed in the Church when any one, only in name a brother, is ashamed or afraid, because of the many good men with whom he lives, to break into that unity of the Church's faith and peace which he abhors. And because the chief priests sought to lay hold of our Lord but could not by themselves, they tried to accomplish it by the hands of the governor; as it follows, And they watched him, &c.