Theophylact of Bulgaria
They were angry with the Lord, for having cast out of the temple those who had made it a place of merchandize, and therefore they come up to Him, to question and tempt Him. Wherefore it is said: And they come again to Jerusalem: and as he was walking in the temple, there come to him the Chief Priests, and the Scribes, and the elders, and say unto him, By what authority doest thou these things? and who gave thee authority to do these things? As if they had said, Who art thou that doest these things? Dost thou make thyself a doctor, and ordain thyself Chief Priest?
Further, they said this, thinking to bring Him to judgment, so that if He said, by mine own power, they might lay hold upon Him; but if He said, by the power of another, they might make the people leave Him, for they believed Him to be God. But the Lord asks them concerning John, not without a reason, nor in a sophistical way, but because John had borne witness of Him. Wherefore there follows: And Jesus answered and said unto them, I will also ask of you one question, and answer me, and I will tell you by what authority I do these things. The baptism of John, was it from heaven, or of men? answer me.