Pseudo-Chrysostom — as excerpted in the Catena Aurea on Matthew 21:10-16

“And Jesus entered into the temple of God. This was the part of a good Son to haste to His Father’s house, and do Him honour; so you then becoming an imitator of Christ as soon as you enter into any city, first run to the Church. Further, it was the part of a good physician, that having entered to heal the sick city, he should first apply himself to the source of the sickness; for as every thing good cometh out of the temple, so also doth every evil. For when the priesthood is sound, the whole Church flourishes, but if it is corrupt, faith is impaired; and as when you see a tree whose leaves are pale-coloured you know that it is diseased at its root, so when you see an undisciplined people conclude without hesitation that their priesthood is unsound.”