St John of Kronstadt - Pray without ceasing...

Pray without ceasing, calling upon the name of the life-giving Trinity in order that your soul should not be suddenly overwhelmed by any passion, pride, or envy, or malice and hatred, or avarice, or covetousness, or gluttony, or anger and irritability, or harsh judgment or scorn, or falsehood and calumny, or any such passion; for we walk amongst snares every hour, every minute of our life. Let the eyes of your heart be on guard every hour, every minute.

Let your heart be watchful, not only during the day, but also during the night, in accordance with the Scriptures.