Catholic Activity: Why Forty Days?
An explanation of the significance of the number of 40 days in our Lenten season.
St. Augustine accounts for our forty day fast:
The number 40 is put before us as sacred and in some way representing perfection. Of this, I think, dearly beloved, you are aware; for there are many instances you know to be found in holy. Scripture. You are well aware that fasting has been hallowed by this number. Moses fasted for forty days as did Elias; and our Lord and Savior Jesus Christ himself kept a fast of the same number of days.
Moses represents the law; Elias, the prophets; and our Lord, the Gospel.
And so in the matter of fasting, the number 40 is recommended to us whether under the law, the prophets, or the Gospel. Now the great fast, binding us all, is to abstain from sin and unlawful pleasure. The perfect fast is "to forego irreverent thoughts and worldly appetites, and to live, in this present world, a life of order, justice and holiness.
Activity Source: Holy Lent by Eileen O'Callaghan, The Liturgical Press, Collegeville, Minnesota, 1975