Attributed to Theophan the Recluse
«"To pray is to descend with the mind into the heart, and there to stand before the face of the Lord, ever-present, all-seeing, within you."»
Misattributed
Verdict
It is not in Theophan the Recluse's work
Widely circulated in English, it comes from the anthology The Art of Prayer (1936; English translation 1966), which assembles and sometimes condenses fragments of his letters. The idea is his and appears in letters 45 and 58 of What Is the Spiritual Life; the exact Russian wording has not been located.
Source: Chariton de Valaam, higúmeno (comp.). The Art of Prayer: An Orthodox Anthology. Trad. E. Kadloubovsky y E. M. Palmer; ed. e introd. Timothy Ware. Londres: Faber & Faber, 1966 (ISBN 9780571068999). Original: Умное делание. О молитве Иисусовой, Sortavala, 1936.
What they did say
Verified words of Theophan the Recluse
«The Christian life is zeal and strength to abide in active communion with God, through faith in our Lord Jesus Christ, with the help of God's grace, by fulfilling His holy will, to the glory of His most holy name.»
«Путь ко спасению», sección I, «Как начинается в нас христианская жизнь?».
«Prayer is the first task of the Christian life.»
«Четыре слова о молитве», palabra I, «Начало науке молитвенной».
«Prayer itself is the rising in our heart, one after another, of reverent feelings towards God: self-abasement, devotion, thanksgiving, praise, petition, earnest prostration, contrition, submission to God's will and the like.»
«Четыре слова о молитве», palabra I.