In his 30th year (15th year of the emperor Tiberius, ? A.D. 25-26) John began his public life in the "wilderness of Judaea," the wild district that lies between the Kedron and the Dead Sea, and particularly in the neighbourhood of the Jordan, where multitudes were attracted by his eloquence. The central theme of his preaching was, according to the Synoptic Gospels, the nearness of the coming of the Messianic kingdom, and the consequent urgency for preparation by repentance. John was evidently convinced that he himself had received the divine commission to bring to a close and complete the prophetic period, by inaugurating the Messianic age. He identified himself with the "voice" of Isa. xl. 3. Noteworthy features of his preaching were its original and prophetic character, and its high ethical tone, as shown e.g. in its anti-Pharisaic denunciation of trust in mere racial privilege (Matt. iii. 9). Herein also lay, probably, the true import of the baptism which he administered to those who accepted his message and confessed their sins. It was an act symbolizing moral purification (cf. Ezek. xxxvi. 25; Zech. xiii. 1) by way of preparation for the coming "kingdom of heaven," and implied that the Jew so baptized no longer rested in his privileged position as a child of Abraham. John's appearance, costume and habits of life, together with the tone of his preaching, all suggest the prophetic character. He was popularly regarded as a prophet, more especially as a second Elijah. His preaching awoke a great popular response, particularly among the masses of the people, "the people of the land." He had disciples who fasted (Mark ii. 18, &c.), who visited him regularly in prison (Matt. xi. 2, xiv. 12), and to whom he taught special forms of prayer (Luke v. 33, xi. 1). Some of these afterwards became followers of Christ (John i. 37). John's activity indeed had far-reaching effects. It profoundly influenced the Messianic movement depicted in the Gospels. The preaching of Jesus shows traces of this, and the Fourth Gospel (as well as the Synoptists) displays a marked interest in connecting the Johannine movement with the beginnings of Christianity. The fact that after the lapse of a quarter of a century there were Christians in Ephesus who accepted John's baptism (Acts xviii. 25, xix. 3) is highly significant. This influence also persisted in later times. Christ's estimate of John (Matt. xi. 7 seq.) was a very high one. He also pointedly alludes to John's work and the people's relation to it, in many sayings and parables (sometimes in a tone of irony). The duration of John's ministry cannot be determined with certainty: it terminated in his imprisonment in the fortress of Machaerus, to which he had been committed by Herod Antipas, whose incestuous marriage with Herodias, the Baptist had sternly rebuked. His execution cannot with safety be placed later than A.D. 28.