The first act was the renunciation of the Devil and all his works.  This, as described by Tertullian, was done first in the Church “under the hand of the Bishop,” and again immediately before entering the water De. Cor. Mil. c. 3..  Cyril speaks of the latter occasion only.  “First ye entered into the outer chamber of the Baptistery, and there facing towards the West (as the region of darkness) ye heard the command to stretch forth your hand, and as in the presence of Satan to renounce him Myst. i. § 2..”  For the formula of renunciation in the Apostolical Constitutions, see note 2 on Mystag. i. § 8; it corresponds closely with Cyril’s, except that this is addressed to Satan as if personally present:  “ I renounce thee, Satan § 4., and all thy works § 5., and all thy pomp § 6., and all thy worship § 8..”