. . . [W]hen you are about to pass over the threshold of the gateway, say this word first: I leave your ranks, Satan, and your pomp, and your service, and I join the ranks of Christ. And never go forth without this word. This shall be a staff to you, this your armor, this an impregnable fortress, and accompany this word with the sign of the cross on your forehead. For thus not only a man who meets you, but even the devil himself, will be unable to hurt you at all, when he sees you everywhere appearing with these weapons; and discipline yourself by these means henceforth, in order that when you receive the seal you may be a well-equipped soldier, and planting your trophy against the devil, may receive the crown of righteousness, which may it be the lot of us all to obtain, through the grace and lovingkindness of our Lord Jesus Christ, with whom be glory to the Father and to the Holy Spirit for ever and ever— Amen.
+ St. John Chrysostom, Instructions to Catechumens