Those who have not yet obtained true prayer of the heart, can find help in violence in bodily prayer—I mean stretching out the hands, beating the breast, sincere raising of the eyes to heaven, deep sighing, and frequent prostrations. But often they cannot do this owing to the presence of other people, and so the demons especially choose to attack them just at this very time.
And as we have not yet the strength to resist them by firmness of mind and the invisible power of prayer, we yield to our enemies.
If possible, go apart for a brief space. Hide for a while in some secret place. Raise on high the eyes of your soul, if you can; but if not, your bodily eyes. Hold your arms motionless in the form of a cross, in order to shame and conquer the evil one by this sign. Cry to Him who is mighty to save, using no subtle expressions but humble speech, preferably making this your prelude: “Have mercy on me, for I am weak”. Then you will know by experience the power of the Most High, and with invisible help you will invisibly drive away the invisible ones.
He who accustoms himself to wage war in this way will soon be able to put his enemies to flight solely by spiritual means; for the latter is a recompense from God to doers of the former; and rightly.
Based on Saint John of the Ladder
Waiting in courtyard for the meal. Vatopedi monastery, Mount Athos
— Source: asceticexperience.com