And now why tarriest thou? arise, and be baptized, and wash away thy sins, calling on the name of the Lord. Arise, and be baptized - Take now the profession of Christ's faith most solemnly upon thee, by being baptized in the name of Father, Son, and Holy Spirit.
Wash away thy sins, etc. - Let this washing of thy body represent to thee the washing away of thy sins: and know that this washing away of sin can be received only by invoking the name of the Lord.