Why was baptism not an admission ceremony for St. John the Baptist’s inner circle of disciples?

For St. John the Baptist, baptism was not an admission ceremony for his inner circle of disciples because it served a different, specific purpose. Instead of functioning as an initiation rite into a group, the act of immersion in running water was a symbolic expression of repentance in preparation for the imminent Final Judgment of God.1

The rite was intended to be accompanied by a righteous life, both before and after the act, rather than acting as a sacrament that conveyed forgiveness or established a new religious identity. John’s baptism was primarily an anticipatory submission to the coming world judgment, which he described as a future "baptism" by the Holy Spirit and fire. Consequently, it was not conceived as a means of superseding Judaism or marking off a new community of believers.1