St Gregory the Great on Lent as a tithe of time
Greg., Hom. in Ev., 16, 5:
Or, as by the Law we offer the tenth of our goods, 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.
His math is a little off for the current calendar, but let’s not quibble over feast dates.
