Bitterness never serves any purpose but to embitter. St Vincent Ferrer says there can be no profit from a sermon if it is not preached from depth of compassion. (…) The spirit of compassion is the one means of touching the hearts of people. If we fight the devil in a spirit of pride and complacency we shall never vanquish him, for his pride and complacency are greater than ours; but if we work against him in humility we shall overcome him, for he has none of these weapons, and he is unable to defend himself against them. [p. 103]

(St Vincent de Paul. From Jacques Delarue, The Holiness of Vincent de Paul, Geoffrey Chapman Ltd, London 1960, 132 pp)