In the second half of Homily 20, St. Isaac the Syrian lays out for us the beauty of maintaining Night Vigils. He values it so much that he tells us that we should never remove it from our spiritual life. Nor are we to dissipate our toil by becoming inattentive and negligent in our daily life. If we cultivate our converse with God throughout the day so that it conforms to our night's mediation then in a very short while we shall have embraced Jesus' bosom. Dominion over one's thoughts and purity and concentration is granted to the mind that allows it to gaze upon and understand the mysteries revealed in the Scriptures. Even in illness when other disciplines are relaxed Vigils gain for the mind a steadfastness in prayer. If we maintain the practice throughout our lives we will behold the glory experienced by the righteous.
This isn't without struggle. We must be willing to endure and persevere through times of heaviness and coldness and learn through these experiences that great fruit is received and suddenly our strength will return to us. We will be overcome with wonder and purifying tears will flow.
If after fasting, prayer and Vigils have led to the taming of the body, the arousal of appetites should return, Isaac warns us that we must through repentance search for the source of pride that diminishes this great gift until our hearts are once again brought to rest in God.