A Wondrously Angry God

Calvin, in the Institutes, on the purpose of God's anger on earth, 3.2.12:

From the other side we see that God, while not ceasing to love his children, is wondrously angry toward them; not because he is disposed of himself to hate them, but because he would frighten them by the feeling of his wrath in order to humble their fleshly pride, shake off their sluggishness, and arouse them to repentance. Therefore, at the same time they conceive him to be at once angry and merciful toward them, or toward their sins. For they unfeignedly pray that his wrath be averted, while with tranquil confidence they nevertheless flee to him for refuge.