Luke 7:28
ESV - 28 I tell you, among those born of women none is greater than John. Yet the one who is least in the kingdom of God is greater than he.
For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
In agreement with the above, John was of the old covenant high priesthood which was successional and of the earthly lineage of Aaron as opposed to the heavenly, Melchizedek, lineage of priesthood by faith in Jesus Christ alone. One was of the flesh; one of the spirit. Jn 6:63; Heb 9:14; Rev 5:10.