In the first place, it is the affliction of the flesh—a victim able to appease the Lord by means of the sacrifice of humiliation—in making a libation to the Lord of sordid raiment, together with scantiness of food, content with simple diet and the pure drink of water in conjoining fasts to all this; in inuring herself to sackcloth and ashes. This bodily patience adds a grace to our prayers for good, a strength to our prayers against evil; this opens the ears of Christ our God, dissipates severity, elicits clemency.
…That which springs from a virtue of the mind is perfected in the flesh; and, finally, by the patience of the flesh, does battle under persecution.
Tertullian
On Patience
Chapter XIII