My soul, O my soul, rise up! Why are you sleeping? The end draws near, and soon you will be troubled. Watch, then, that Christ your God may spare you, for He is everywhere present and fills all things.
From the Great Canon of Andrew of Crete
Wisdom from the Church Fathers
But if a person is constantly mindful of God, he will rejoice: as the psalmist says, "I remembered God, and I rejoiced" (Psalms 77:3). For when the intellect is gladdened by the remembrance of God, then it forgets the afflictions of this world, places its hope in Him, and is no longer troubled or anxious.
St. Peter of Damaskos, "JOY" (from "The 24 Discourses), "The Philokalia vol. III," - pp. 260 - 263.