Gregory the Great
Catena Aurea · Matthäusevangelium 4
Then was Jesus led up of the Spirit into the wilderness to be tempted of the Devil. And when He had fasted forty days and forty nights, He was afterward an hungred.
(Hom. in. Ev. 16. 5.) The Creator of all things took no food whatever during forty days. We also, at the season of Lent as much as in us lies afflict our flesh by abstinence. The number forty is preserved, because the virtue of the decalogue is fulfilled in the books of the holy Gospel; and ten taken four times amounts to forty. Or, because in this mortal body we consist of four elements by the delights of which we go against the Lord’s precepts received by the decalogue. And as we transgress the decalogue through the lusts of this flesh, it is fitting that we afflict the flesh forty-fold. Or, as by the Law we offer the tenth of ourgoods, so we strive to offer the tenth of our time. And from the first Sunday of Lent to the rejoicing of the paschal festival is a space of six weeks, or forty-two days, subtracting from which the six Sundays which are not kept there remain thirty-six. Now as the year consists of three hundred and sixty-five, by the affliction of these thirty-six we give the tenth of our year to God.