The Moral Reflections on Job by Pope St Gregory the Great

If we receive good from the hand

of God,

why should we not

also receive evil?

Paul saw the riches of wisdom within himself though he himself was outwardly a corruptible body, which why he says We have this treasure in earthen vessels. In Job, then, the earthenware vessel felt his gaping sores externally; while this interior treasure remained unchanged. Outwardly he had gaping wounds but that did not stop the treasure of wisdom within him from welling up and uttering these holy and instructive words: If we have received good at the hand of the Lord, shall we not receive evil? By the good he means the good things given by God, both temporal and eternal; by evil he means the blows he is suffering from in the present. Of those evils the Lord says, through the prophet Isaiah,
I am the Lord, unrivalled,
I form the light and create the dark.
I make good fortune and create calamity,
it is I, the Lord, who do all this.
I form the light, and create the dark, because when the darkness of pain is created by blows from without, the light of the mind is kindled by instruction within.
I make good fortune and create calamity, because when we wrongly covet things which it was right for God to create, they are turned into scourges and we see them as evil. We have been alienated from God by sin, and it is fitting that we should be brought back to peace with him by the scourge. As every being, which was created good, turns to pain for us, the mind of the chastened man may, in its humbled state, be made new in peace with the Creator.
We should especially notice the skilful turn of reflection he uses when he gathers himself up to meet the persuading of his wife, when he says If we have received good at the hand of the Lord, shall we not receive evil? It is a great consolation to us if, when we suffer afflictions, we recall to remembrance our Maker’s gifts to us. Painful things will not depress us if we quickly remember also the gifts that we have been given. As Scripture says, In the day of prosperity do not forget affliction, and in the day of affliction, do not forget prosperity.
Whoever, in the moment of receiving God’s gifts but forgets to fear possible affliction, will be brought low by his presumption. Equally, whoever in the moment of suffering fails to take comfort from the gifts which it has been his lot to receive, is thrown down from the steadfastness of his mind and despairs.
The two must be united so that each may always have the other’s support, so that both remembrance of the gift may moderate the pain of the blow and fear of the blow may moderate exuberance at receiving the gift. Thus the holy man, to soothe the depression of his mind amidst his wounds, weighs the sweetness of the gifts against the pains of affliction, saying If we have received good at the hand of the Lord, shall we not receive evil?