Night vigils is the light of the thinking; and by it the understanding is exulted, the thought is collected, and the mind takes flight and gazes at spiritual things and by prayer is rejuvenated and shines brilliantly. Through vigil there are bestowed on a man the earnests of the good things of the life to come and the graces of those gifts, the mysteries of which are indicated in the holy Scriptures.

St. Isaac the Syrian