Ambrose of Milan

For God wishes not His temple to be a house of traffic, but the dwelling-place of holiness, nor does He fix the priestly service in a saleable performance of religion, but in a free and willing obedience.

Catena Aurea by Aquinas ↗

Gregory the Dialogist

And these make the house of God a den of thieves, because when corrupt men hold religious offices, they slay with the sword of their wickedness their neighbours, whom they ought to raise to life by the intercession of their prayers. The temple also is the soul of the faithful, which if it put forth corrupt thoughts to the injury of a neighbour, then is it become as it were a lurking place of thieves. But when the soul of the faithful is wisely instructed to shun evil, truth teaches daily in the temple.

Catena Aurea by Aquinas ↗

Bede

And having entered the temple, He began to cast out those who sold and bought in it, saying to them: It is written, My house is a house of prayer. He who announced the evils to come and immediately entered the temple to cast out those who sold and bought in it, surely showed that the ruin of the people was chiefly due to the fault of the priests. Describing the overthrow and striking those who sold and bought in the temple, He showed in the very act of His work from where the root of destruction originated.

On the Gospel of Luke ↗