Not a particle of time but of consequence; therefore, because of both Jesus and John baptizing.
Question (ζηÌτησις)
Rev., more correctly, questioning. Question would be ζηÌτημα, always in the sense of a question in debate. The word here represents the process of inquiry.
Between (ἐκ)
Rev., correctly, on the part of. Literally, proceeding from. The rendering of the A.V. does not show with which party the discussion originated. The Greek distinctly states that the question was raised by the disciples of the Baptist.
The Jews
The best texts read ἹουδαιÌου, with a Jew. Possibly one who asserted that John's baptism might now be dispensed with.
Purifying
Probably not about the familiar ceremonial purifications, but as to whether the baptism of Jesus or of John had the greater purifying power.