The number has deep biblical roots.
Each year the Roman Rite of the Catholic Church celebrates 40 days of prayer and fasting before the great celebration of Easter. This number is very symbolic and has deep ties to multiple biblical events.
Purification and renewal
The first mention of 40 occurs in the book of Genesis. God proclaims to Noah, “For in seven days I will send rain upon the earth forty days and forty nights; and every living thing that I have made I will blot out from the face of the ground” (Genesis 7:4). This event connects the number 40 to purification and renewal, a time when the earth was washed clean and made anew.
Recognizing our sinfulness
In Numbers we see the number 40 again, this time as a type of penance and punishment imposed on the people of Israel for disobeying God. They had to wander in the desert for 40 years so that a new generation could inherit the Promised Land, instead of the people who did not trust in God’s plan for them.
Repentance and conversion of heart
In the book of Jonah, the prophet proclaims to Nineveh, “Yet forty days, and Nineveh shall be overthrown! And the people of Nineveh believed God; they proclaimed a fast, and put on sackcloth, from the greatest of them to the least of them” (Jonah 3:4). This again ties the number to spiritual renewal and conversion of heart.
A time of prayer and preparation
The prophet Elijah, before he encountered God on Mount Horeb, traveled for forty days, “And he arose, and ate and drank, and went in the strength of that food forty days and forty nights to Horeb the mount of God (1 Kings 19:8). This connects 40 to a time of spiritual preparation, a time when the soul is led to a place where it can hear the voice of God.
Engaging in a spiritual battle
Before embarking on his own public ministry, Jesus “was led up by the Spirit into the wilderness to be tempted by the devil. And he fasted forty days and forty nights” (Matthew 4:1-2). In continuity with the past, Jesus sets out to pray and fast for 40 days, combating temptation and preparing himself for proclaiming the Gospel to others.
In the end, all of these episodes in the Gospel reveal different reasons why the number 40 was selected for the season of Lent. Together they provide for us a spiritual guide for Lent, inviting us to open our hearts to God.