Letters of St. Ambrose of Optina. Letter 373.
The enemy confuses you with various perplexities. The Holy Fathers advise not to be afraid, when calling the name of God, especially since you started this work not on your own, but with the blessing. And do not assign special significance to things you do not understand, not rejecting and not accepting them, as the venerable Mark the Ascetic advised to spiritual babes, such as the fact that you saw Christ crucified inside the heart, and the Savior sitting in prison in red clothes, and some strange light. Leave this, and everything similar to this to the will of God, telling yourself: "Only God knows what is good and salutary." Read all places about delusion in the Philokalia and beware of the indicated signs of delusion. Leave the rest to the will of God. You write that when you pray, you look at the heart. The Holy Fathers advise, during prayer, to look inside the heart, and not from above, and not from the side, and especially if the attention of the mind descends below the heart, then lusts of the flesh arise. You write that on the feast of St. John the Evangelist you was exhausted, left the church and went to the cell and, lying on your bed, saw a running enemy, in all its disgrace. Henceforth, if you are exhausted in the church, sit or lie down, but do not leave. In general, know as you yourself read in the books of the Holy Fathers that the enemy does not rebel against anything as much as against the prayer of Jesus. Therefore, as you have begun to keep the Jesus prayer, then do not leave it, but continue, trusting in the mercy and help of God. The Lord and the Queen of Heaven are strong to save us from the evils and troubles inflicted by spiritual enemies.
You also write that some of your sisters refer to the Athos elders. But you do not know them, and they do not know you. Therefore, such a referral cannot be convenient. In addition, in your letter it was said that you had three days of strong excitement of the flesh... Probably, you judged someone, or you were subjected to it for humility and trial.