Saint John of Sinai. "The Ladder of Divine Ascent". Step 30.
28. The power of love is in hope, because by it we await the reward of love.
29. Hope is a wealth of hidden riches. Hope is a treasure of assurance of the treasure in store for us.
30. It is a rest from labours; it is the door of love; it is the superannuation of despair; it is an image of what is absent.
31. The failure of hope is the disappearance of love. Toils are bound by it. Labours depend on it. Mercy encircles it.
32. A monk of good hope is a slayer of despondency; with this sword he routs it.
33. Experience of the Lord’s gift engenders hope; he who is without experience remains in doubt.
34. Anger destroys hope, because hope does not disappoint,  but a passionate man has no grace. 
 Romans v, 5.
 Or, ‘an angry man is not beautiful’ (Proverbs xi, 25).