Baptism in the time of Paul was three things. It was adult baptism; it was instructed baptism; and, wherever possible, it was baptism by total immersion. [author's emphasis] Therefore the symbolism of baptism was manifest. As the waters closed over the man's head, it was as if he died; as he rose up again from the water, it was as if he rose to new life. Part of him was dead and gone for ever; he was a new man risen to a new life.
But, it must be noted, that symbolism could become a reality only under one condition. It could become real only when a man believed intensely in the life and death and resurrection of Jesus Christ. It could only happen when a man believed in the effective working of God which had raised Jesus Christ from the dead and could do the same for him. Baptism for the Christian was in truth a dying and a rising again, because he believed that Christ had died and risen again and that he was sharing in the experience of his Lord.
You go, Bill!
William Barclay, The Daily Study Bible Series: The Letters to the Philippians, Colossians, and Thessalonians, Revised edition, (Philadelphia, The Westminster Press, 1975), p. 140.