This question not only silenced the scribes but is also a good question for modern Christians. Many have maligned John's baptism, saying it was inadequate and valid only for a few years at most. There are good reasons to accept it as valid Christian baptism (see notes on Matthew 3:6,8,11,15,16).

Source:

KJV Defenders Study Bible, by Dr. Henry Morris, Ph.D.
Publisher: Thomas Nelson
Language: English
DEF 10 ISBN 0-529-10444-x
DEF 10-1 ISBN 0-529-10445-8