Matthew Poole and continuators on John 1:25

25 And they asked him, and said unto him, Why Baptizest thou then, if thou be not that Christ, nor Elias, neither that Prophet ?

The Pharisees themselves would allow the Messiah, or Elias, or a Prophet, to make any additions to, or alterations in the Worship of God, but none else: Hence it is, they ask, by what Authority he Baptized, if he were none of these? From whence we may learn, That although they might have some umbrage of that Baptismal washing which was under the Gospel, to commence into a Sacrament, or foederal sign in the washing of their Proselites, or of Jewish Children when they were Circumcised; yet Iohn's Action was looked upon as new, who Baptized adult Jews; now the care of the Sanhedrim was to keep the Worship of God incorrupt, and the Pharisees amongst them had a particular Zeal in the case, especially so far as the Traditions of the Elders were concerned.