The stone then which the builders rejected, has become the cornerstone of the Church. For the Church is the corner, joining together Jews and Gentiles; and this corner has been made by the Lord, and is wonderful in in the eyes of the faithful; for miracles meet with detraction from the faithless. The Church indeed is wonderful, as it were resting on wonders, for the Lord worked with the Apostles, and confirmed the word with signs. And this is what is meant, when it is said, "This was the Lord's doing, and it is marvelous in our eyes".
But the Chief Priests showed that those things which the Lord had spoken were true; which is proven from what follows: "And they sought to lay hold on him; for He Himself is the heir", whose unjust death He said was to be revenged by the Father. In a moral sense, each of the faithful, when the Sacrament of Baptism is entrusted to him, receives a vineyard on loan, which he is to cultivate. But the servant sent to him is mistreated, beaten, and cast out, when the word is heard by him and despised, or, what is worse, even blasphemed; further, he kills, as far as in him lies, the heir, who has trampled under foot the Son of God.
The evil tenant is destroyed, and the vineyard given to another, the humble shall be enriched with that gift of grace, which the proud man has scorned. And it happens daily in the Church, that the Chief Priests wishing to lay hands on Jesus, are held back by the multitude, when someone, who is a brother only in name, either blushes or fears to attack the unity of the faith of the Church, and of its peace, though he loves it not, on account of the number of good brethren who dwell together within it.
On the Gospel of Mark (St. Bede the Venerable)
Explanations on the New Testament (St. Theophylact of Ochrid)