O CHRIST, the true light that lighteth and halloweth every man that cometh into the world (Jn 1:9), let the light of thy countenance be signed upon us (Ps 4:6 LXX), that in it we might see the light unapproachable (1 Tim 6:16), and direct our steps to the doing of thy commandments (cf. Ps 118:5), at the intercessions of thy wholly undefiled Mother, and of all thy saints. Amen.
Final blessing at the First Hour, for the Feast of the Theophany of our Lord and Saviour Jesus Christ. Source.