Patristic Wisdom: Looking to the Eighteenth Sunday after Pentecost

Now when He came into the temple, the chief priests and the elders of the people confronted Him as He was teaching, and said, “By what authority are You doing these things? And who gave You this authority?” But Jesus answered and said to them, “I also will ask you one thing, which if you tell Me, I likewise will tell you by what authority I do these things: The baptism of John—where was it from? From heaven or from men?” And they reasoned among themselves, saying, “If we say, ‘From heaven,’ He will say to us, ‘Why then did you not believe him?’ But if we say, ‘From men,’ we fear the multitude, for all count John as a prophet.” So they answered Jesus and said, “We do not know.” And He said to them, “Neither will I tell you by what authority I do these things. (Matthew 21:23–27)

The Pharisees had seen many things more worthy to call great miracles, but they were now especially worried, and asked the Lord by what authority He did these things. Again, the presentation of these facts encloses a profound mystery of the future. The Pharisees found it especially necessary to question Him about events in which a foreshadowing of general danger was expressed. The Lord responded that He would explain by what power He was doing these things, if they would tell Him whether they thought that John’s baptism was of heaven or of men. But they hesitated at the danger of giving a response. If they acknowledged that it was from heaven, they would be found guilty for not believing in the authority of heavenly testimony; if they said it was from men, they feared the crowd since many regarded John as a prophet. So they responded by saying that they did not know (they certainly knew it was from heaven), because they were afraid that an admission of truth would prove them wrong. Plainly they had spoken with the intention of deceiving Him about themselves. Because of their unbelief they did not know John’s baptism was from heaven. Even if John’s baptism had been of human [origin], they could not know it, because he was not.

Hilary of Poitiers, Commentary on Matthew 21.10

In answering that they did not know, they lied. Consequently, it was in accordance with their response for the Lord too to say: Neither do I know, but the truth cannot lie; and He says: “Neither do I tell you.” By this He shows both that they know, but they are unwilling to give the answer; and that He knows, and the reason He does not tell is because they are being silent about what they know. And immediately He adds a parable by which he convicts them of impiety and teaches that the kingdom of God is to be transferred to the Gentiles.

Jerome, Commentary on Matthew 3.21