One of the riddles posed by the discovery of the Dead Sea Scrolls is what John the Baptist's relationship to the Essenes and the Qumran community would have been like. Was he a member of that community or not? Even if we approach this question cautiously, it seems a strange and striking coincidence that two groups in the same region (the Judaea, wilderness) at the same time (the early part of the first century CE) would be teaching a similar ideology (repentance, ritual purification, and an imminent eschatology), yet not have any contact or relationship one with another, be it positive or negative.
In a classic study, Otto Betz proposed that John the Baptist grew up in the Essene community, but left it to act as a prophet, preaching repentance to the wider Jewish community.
I find this view not only appealing, but very persuasive too. It takes into account not only the similarities but also the differences between John and the Essenes.
I see no reason to believe that John lived in a cultural vacuum. Where and who we grow up around influences the path we take and the way in which we view things, be we prophets or be we laymen.
In those days came John the Baptist, preaching in the wilderness of Judaea,
And saying, Repent ye: for the kingdom of heaven is at hand.
For this is he that was spoken of by the prophet Esaias, saying, The voice of one crying in the wilderness, Prepare ye the way of the Lord, make his paths straight.
And the same John had his raiment of camel's hair, and a leathern girdle about his loins; and his meat was locusts and wild honey.
The Gospel of Matthew describes John the Baptist in terms reminiscient of the prophet Elijah's physical appearance, but also as the fulfilment of Isaiah 40:3.
The Essene community saw the same Isaiah verse as a call to separate themselves from the community at large and live in the wilderness as part of God's true society.
When such men as these come to be in Israel, conforming to these doctrines, they shall separate from the dwelling-place of the men of perversion in order to go to the wilderness to prepare there the way of truth, as it is written (Is.40:3): ‘In the wilderness prepare the way of the LORD, make straight in the desert a highway for our God!’—this means the expounding of the Law, decreed by God through Moses for obedience, that being defined by what has been revealed for each age, and by what the prophets have revealed by His holy spirit.
-Manual of Discipline 8:12–16.
This Manual of Discipline (Serech ha-Yahad, or the Community Rule) contains the rules of conduct to be followed by all those associated with the Essenes.
Josephus writes that although the Essenes did not utterly reject marriage, they would seek out "other persons' children, while they are pliable, and fit for learning, esteeming them to be of their kindred, and form them according to their own manners." It seems more than likely that if John was brought up in an Essene environment then the same Isaiah verse that formed a large part of the Essene identity would shape the way that John (and his followers) conceived of his own mission.
Ritual purification was important to all Jewish groups, and Qumran was no exception, with several ritual pools (mikveh) being found there. still, the mere ritual of immersion was considered ineffective if the individual did not repent and accept upon himself God's commandments, as interpreted by the Yahad (the way the Essenes seemed to have refered to their community).
So shall all together comprise a Yahad whose essence is truth, genuine humility, love of charity and righteous intent, caring for one another after this fashion within a holy society, comrades in an eternal fellowship...
Yet he cannot be justified by what his willful heart declares lawful, preferring to gaze on darkness rather than the ways of light. With such an eye he cannot be reckoned faultless. Ceremonies of atonement cannot restore his innocence, neither cultic waters his purity. He cannot be sanctified by baptism in oceans and rivers, nor purified by mere ritual bathing. Unclean, unclean shall he be all the days that he rejects the laws of God, refusing to be disciplined in the Yahad of His society.
-Manual of Discipline 2:24-25, 3:3-6.
Josephus writes of John the Baptist that he was "a good man, and commanded the Jews to exercise virtue, both as to righteousness towards one another, and piety towards God, and so to come to baptism; for that the washing [with water] would be acceptable to him, if they made use of it, not in order to for the remission of some sins [only], but for the purification of the body; supposing still that the soul was thoroughly purified beforehand by righteousness."
Otto Betz described another common thread between John and the Essenes, the combination of the priestly and the prophetic.
"In ancient Israel the spirit of prophecy often opposed the theology of the priests (see, for example, Amos 5:22; Isaiah 1:11–13; Jeremiah 7:21–26). The prophets warned the people not to rely too heavily on the Temple and on the atoning effect of sacrifice. Both the Essenes and John the Baptist, however, succeeded in combining the prophetic and the priestly ideals in a holy life, ritually pure but characterized by repentance and the expectancy of the final judgment. John’s disciples were known to fast (Mark 2:18) and to recite their special prayers (Luke 11:1). These two acts of piety also appear in the Qumran texts. Infraction of even minor rules was punished by a reduction in the food ration, which meant severe fasting (Manual of Discipline 7:2–15). And there are several special prayers in the Dead Sea Scrolls. Among them are the beautiful Thanksgiving Hymns from the scroll found in Cave 1. Cave 11 also produced a scroll of psalms in which new prayer were inserted into a series of Psalms of David.
The Qumran Essenes separated themselves from the Jerusalem Temple and its sacrificial cult. The Temple’s offerings of animals were replaced by the “offerings of the lips” (that is, prayers) and by works of the Law. Man must render himself to God as a pleasing sacrifice; he must bring his spirit and body, his mental and physical capacities, together with his material goods and property, into the community of God. In this community all these gifts will be cleansed of the pollution of selfish ambition through humble obedience to the commandments of God (Manual of Discipline 1:11–13)."
In ancient Israel, the temple linked God and man and the sacrifices in it atoned for Israel's sins and transgressions. The Essenes considered the contemporary priests who officiated at the temple to be corrupt and perverse. The separatist community of the Essenes saw itself as truly holy, and applied the role of the temple to their community.
When such men as these come to be in Israel, then shall the party of the Yahad truly be established, an "eternal planting" (Jubilees 16:26), a temple for Israel, and- mystery!- a Holy of Holies for Aaron; true witnesses to justice, chosen by God's will to atone for the land and to recompense the wicked their due. They will be "the tested wall, the precious cornerstone" (Isa 28:16) whose foundations shall neither be shaken nor swayed, a fortress, a Holy of Holies for Aaron, all of them knowing the Covenant of Justice, and thereby offering a sweet savor. They shall be a blameless and true house in Israel, upholding the covenant of eternal statutes. They shall be an acceptable sacrifice, atoning for the land and ringing in the verdict against evil, so that perversity ceases to exist.
-The Manual of Discipline 8:4-10.
John taught a similar doctrine.
Bring forth therefore fruits meet for repentance:
And think not to say within yourselves, We have Abraham to our father: for I say unto you, that God is able of these stones to raise up children unto Abraham.
Acording to Betz, "this famous saying contains a marvelous play on words in Hebrew. “Children” is banim; “stones” is abanim. The saying thus presupposes the idea of a living temple “of men.” John is saying that God can create genuine children of Abraham “from these stones” and build them into the sanctuary of His community. In the Temple Scroll from Qumran, God promises that he will “create” a sanctuary at the beginning of the new age; this he will do according to the covenant made with Jacob at Bethel (Temple Scroll 29:7–10). At Bethel, Jacob had declared: “This stone [the pillar that Jacob had erected] shall become the house of God” (Genesis 28:22). Both the Qumran community and John the Baptist believed in the creative power of God that will manifest itself at the end of time, as it did in the beginning. Then God will establish the true sanctuary and the ideal worship, which are anticipated both in the life of the Qumran community and in the life that John preached."
There are many more similarities between the life and teachings of John and the Essenes, but there are also some important differences which need to be pointed out.
The Essenes were a closed community within Israel, concerned with their own salvation, whereas John saw himself as a reforming prophet reaching out to all his people.
He didn't turn the people into monks living in the wilderness, but after repenting and being baptised they went back to their lives, their families and their jobs. John was the voice in the wlderness, the people weren't.
John also was outspoken in his politics, attacking the Herodians for their moral depravity, something the Essenes do not appear to have done.
I will leave Otto Betz the final word.
Both biblical traditions—the priestly one and the prophetic one—influenced the Essenes just as they did John the Baptist.
I believe that John grew up as an Essene, probably in the desert settlement at Qumran. Then he heard a special call of God; he became independent of the community—perhaps even more than the Essene prophets described by Josephus. With his baptism of repentance, John addressed all Israel directly; he wanted to serve his people and to save as many of them as possible.
The Essenes of Qumran no doubt prepared the way for this prophetic voice in the wilderness. They succeeded in combining Israel’s priestly and prophetic heritage in a kind of “eschatological existence.” The Essenes radicalized and democratized the concept of priestly purity; they wanted a true theocracy and sought to turn the people of God into a “kingdom of priests” (Exodus 19:5–6).
A particular motif of their peculiar piety was the eschatological hope. In the age to come, they believed, there would be only one congregation of holy ones in heaven and on earth; then angels and men would worship together. Therefore, the liturgy and the sacred calendar used in heaven for the time of prayer and the celebration of the feasts served as a model for Essene worship even in the present. In heaven, animals are not sacrificed and offered to God; the angels use incense and sing hymns of praise. Therefore, on earth they had no need of the Jerusalem Temple. The Essenes believed that a living sanctuary of holy men could render a more efficient ministry of atonement than animal sacrifices, offered by an unclean priesthood (Manual of Discipline 8:6–10; 9:4–5).
But the Essenes also incorporated the traditions of the prophets into their beliefs. The prophet had little if anything to do with the Temple and sacrifice; the prophet tried to accomplish atonement through his personal commitment and effort to change the hearts of his audience. Because the Essenes were a movement of repentance, they adopted the prophetic tradition, despite their leadership of priests. Their Teacher of Righteousness was a priest who acted in a prophetic way.
This was true as well for John the Baptist. He was the son of a priest and practiced the laws of priestly purity in a radical way. But in his ministry for Israel he acted as a prophet, as the Elijah redivivusf to announce the coming of the Messiah. In his baptism, both traditions were combined, just as they were in the Essene philosophy: the priestly laws of ritual purity were combined with the prophetic concern for repenting, returning to God and offering oneself to Him. Accordingly, it is reasonable to conclude that John the Baptist was raised in the tradition of the Essenes and may well have lived at Qumran before taking his message to a wider public.
-Otto Betz, Was John the Baptist an Essene?
Betz, Otto. Was John the Baptist an Essene?. Bible Review, Dec 1990, 18-25.
Josephus, The Jewish Wars, 2.8.2
Josephus, Antiquities of the Jews, 18.5.2.
 Betz, BR, Dec 1990.