This knowledge becomes for him the foundation and the beginning of his coming unto all good and beautiful things.
When a man knows and perceives that he really and in truth is weak, then he restrains his soul from profuseness which is dissipation of knowledge and he will augment the watchfulness of his soul.
Unless a man has been remiss in some small thing, and a slight negligence has appeared in him, and tempters have surrounded him either with temptations that arouse bodily affections or with temptations which stir the affectable power of the soul, he cannot perceive his own weakness.
Then, however, he recognizes the greatness of God’s help by comparing it with his own weakness.
Thus if he sees that his heart does not rest from fear…, he understands and knows that this whole impulse of his heart denotes some other thing which is lacking and which is very necessary to him, viz. that he needs other help.
For the heart testifies to this within, by the fear that moves in it, denoting the lack of something. And therefore he cannot remain in confidence. For the help of God is necessary for deliverance.
When he knows that he needs divine help, he will frequently pray. And by much beseeching the heart becomes humble, for there is no man who is needy and asking, without being humble. And God will not despise a broken and contrite heart!
Until the heart has become humble, it will not rest from distraction. Humility restrains the heart. And as soon as man has become humble, mercy will surround and envelop him. And when mercy draws near, the heart will perceive help at once, because some confidence and force will also move in it.
When it perceives that divine help approach unto it and that He is its support and its helper, then the heart will be filled with faith at once.
Then it will see and understand that prayer is the port of help, the fountain of salvation, the treasure of confidence, the sheet-anchor amidst the storms, the light in the darkness, the stick of the weak, the shelter at the time of temptations, the medicine at the time of illness, the shield of protection in the battle, the sharp arrow against the enemies.
And because by prayer he has found the entrance unto all this good, he will delight in prayer of faith for ever more, while his heart exults in confidence, not blindly and with words only, as it had been till then.
Isaac the Syrian (c. 630-c. 700): Mystic Treatises, 8, in Mystical Treatises of Isaac of Nineveh, trans. A.J. Wensinck, pp. 70-72.