Prayer is a precious way of communicating with God; it gladdens the soul and gives repose to its affections. You should not think of prayer as being a matter of words. It is a desire for God, an indescribable devotion, not of human origin, but the gift of God's grace. As Saint Paul says: we do not know how to pray as we ought, but the Spirit ... intercedes for us with sighs too deep for words.
~ St John Chrysostom (Hom 6 on Prayer)
(Late 9th century mosaic of John Chrysostom in the nave of the Hagia Sophia.)