An excerpt from a homily of St. Leo the Great

That of which the season of the year and our customary devotion reminds us, we, Dearly Beloved, in our paternal duty, now preach to you, namely; that you must observe the fast of the tenth month, whereby, for the complete harvest of all fruits, there is most fittingly offered to God, the Giver of them, an offering of self mortification. For what can be more salutary for us than fasting, by the practice of which we draw nigh to God, and, standing fast against the devil, defeat the vices that lead us astray.

For fasting was ever the food of virtue. From abstinence there arise chaste thoughts, just decisions, salutary counsels. And through voluntary suffering the flesh dies to the concupiscences, and the spirit waxes strong in virtue. But as the salvation of our souls is not gained solely by fasting, let us fill up what is wanting in our fasting with alms-giving to the poor. Let us give to virtue what we take from pleasure. Let the abstinence of the man who fasts be the dinner of the poor man.

Let us have thought for the protection of the widow, for the welfare of the orphan, for the comforting of those that mourn, for the peace of those who live in discord. Let the stranger be given shelter. Let the oppressed be aided, the naked be clothed, the sick cherished; so that whosoever has offered from his own works of justice a sacrifice of righteousness to God, the Author of all good things, may merit to receive from the Selfsame the reward of a heavenly kingdom.

Let us then fast on the fourth and sixth day of the week. On the sabbath let us likewise keep watch, together with the Blessed Apostle Peter, by the help of whose merits we may obtain that for which we pray, through the mercy of Jesus Christ Our Lord, Who with the Father and the Holy Spirit, liveth and reigneth, world without end, Amen.