Octave of St John, Apostle and Evangelist
In medio Ecclesiae aperuit os ejus; et implevit eum Dominus Spiritu sapientiae et intellectus; stolam gloriae induit eum. * Bonum est confiteri Domino, et psallere nomini tuo, Altissime.
He opened his mouth in the midst of the Church, and the Lord filled him with the spirit of wisdom: he clad him with a robe of glory. * It is good to give praise to the Lord, and to sing to thy name, O Most High.
(Ecclus. 15:5 and Psalm 91:2 from the Introit of Mass)
Ecclesiam tuam, Domine, benignus illustra: ut beati Joannis, Apostoli tui et Evangelistae illuminata doctrinis, ad dona perveniat sempiterna.
Mercifully, O Lord, enlighten thy Church: that being taught by blessed John, thine Apostle and Evangelist, she may come to thy eternal rewards.
The Catholic Encyclopaedia on St John: http://www.newadvent.org/cathen/08492a.htm
Reference for the translation of St Augustine: http://www.breviary.net/propseason/christmas/propseasonchri0103.htm