Matthew 21:25

“The baptism of John, whence was it? etc.] By the baptism of John, is meant the ordinance of water baptism, which was first administered by him; from whence he took the name of John the Baptist: and the doctrine which he preached concerning it, and previous to it, and even the whole of his ministry; which is denominated from a principal part of it, and which greatly distinguished his ministry from all others: and the question put by Christ concerning it is, whence it was? by what authority did John administer the ordinance of water baptism, which had never been administered before by any? who sent him to preach the baptism of repentance for the remission of sins, a doctrine the world had…”

“The baptism of John--meaning his whole mission and ministry, of which baptism was the proper character. whence was it? from heaven, or of men?--What wisdom there was in this way of meeting their question will best appear by their reply. If we shall say, From heaven; he will say unto us, Why did ye not then believe him?--"Why did ye not believe the testimony which he bore to Me, as the promised and expected Messiah?" for that was the burden of John's whole testimony.”

“See also Mark 11:27-33; Luke 20:1-9. Matthew 21:23 When he was come into the temple - That is, probably, into the inner court - the court of the Israelites. They took this opportunity of questioning him on this subject when he was not surrounded by the multitude. By what authority ... - There was a show of propriety in this question. He was making great changes in the affairs of the temple, and they claimed the right to know why this was done, contrary to their permission. He was not “a priest;” he had no civil or ecclesiastical authority as a Jew. It was sufficient authority, indeed, that he came as a prophet and worked miracles. But they professed not to be satisfied with that. These…”

“Why did ye not believe him - Testifying this. Matthew 21:27”

“21:25 John’s ministry, like Jesus’ (see 3:1, 5-6), was controversial, especially after John’s public denouncement of the sins of Herod Antipas (see 14:4). The leaders did not want to acknowledge that John’s ministry was from God, since they had refused to believe John by repenting of their sins (3:2) and accepting Jesus as the Messiah (John 1:29-34).”

“baptism: Mat 3:1-12, Mat 11:7-15, Mat 17:12, Mat 17:13; Mar 1:1-11, Mar 11:27-33; Luk 1:11-17, Luk 1:67-80; Luke 3:2-20, Luk 7:28-35; Joh 1:6, Joh 1:15, Joh 1:25-34, Joh 3:26-36 Why: Luk 20:5; Joh 3:18, Joh 5:33-36, Joh 5:44-47, Joh 10:25, Joh 10:26, Joh 12:37-43; Jo1 3:20 Matthew 21:26”