On Friday of the Second Week of Lent our Church invites us to first read and reflect on a passage from the book of Exodus (19:1-19; 20:18-21) entitled "The promise of the covenant and the revelation of the Lord on Mount Sinai)". Our treasure, which follows, is from a treatise Against Heresies by Saint Irenaeus, bishop.
Saint Irenaeus was a late second century Greek bishop noted for his role in guiding and expanding Christian communities in the southern regions of present-day France and, more widely, for the development of Christian theology.
On Jan. 21, 2022, Pope Francis named a Saint Irenaeus as a Doctor of the Church. Although he has just now been named a doctor of the Church, St. Irenaeus has always been known as a brilliant and orthodox teacher of the faith. The documents of the Second Vatican Council cite 14 references to his work, and the Catechism of the Catholic Church cites him 29 times.
Pope Francis assigned St. Irenaeus the title "doctor of unity" for his efforts to unite the Church, which was competing against the heresy of Gnosticism. Gnosticism taught that the world was created and ruled by a lesser divinity, the demiurge, and that Christ was an emissary of the remote supreme divine being, esoteric knowledge (gnosis) of whom enabled the redemption of the human spirit.
St. Irenaeus might also be the first doctor of the Church to die as a martyr. St. Irenaeus is known mainly for his clear and systematic teaching of the Christian faith because he considered the role of a bishop primarily as a teacher. He was particularly interested in apostolic succession, and he produced one of the earliest lists of the first bishops, going back to the time of the Apostles.
He is most known, though, for his treatises Against All Heresies, written about the year 180. Most of these heresies, as already mentioned, were from Gnosticism. He clearly understood the need to articulate the orthodox faith taught by the Apostles and against those who promoted other ideas that threatened the Apostles' teachings. All this was more than 100 years prior to the Council of Nicaea, which began to codify Christian dogma.
Saint Irenaeus was the last known living connection with the apostles. He is the earliest surviving witness to regard all four of the canonical gospels as essential.
Against Heresies is a work of Christian theology written in Greek about the year 180 by Irenaeus, bishop of Lyon in France. In it, Irenaeus identifies and describes several schools of Gnosticism, and other schools of Christian thought, whose beliefs he rejects as heresy. He contrasts them with orthodox Christianity.
The Book of Exodus, the second book of the Pentateuch, takes its name from a Greek word meaning "departure," highlighting the defining event of Israel's history: the Lord's deliverance of His people from slavery in Egypt. Its Hebrew title, Shemoth — "Names" — comes from its opening line, reminding us that God's saving work unfolds within real history, among real persons whom He knows and calls.
Exodus continues the sacred story where Genesis ends. The descendants of Jacob, once welcomed in Egypt, find themselves oppressed and enslaved. Into this suffering, God reveals Himself not as distant, but as the One who hears the cry of His people. Through Moses, He performs mighty works, freeing Israel and leading them through the Red Sea — an event the Church has long recognized as a powerful foreshadowing of Baptism and redemption.
Yet liberation is only the beginning. At Mount Sinai, God establishes His covenant with Israel. The Law (torah) given through Moses is not merely a set of rules but the framework of a relationship. God saves first; then He teaches His people how to live in the freedom He has given. The moral, civil, and ritual laws form Israel into a holy nation, called to reflect God's own holiness before the world.
A striking portion of Exodus is devoted to the tabernacle, the portable sanctuary where God chooses to dwell among His people. This reveals the deeper purpose of salvation: communion. God does not simply rescue Israel from something — He rescues them for something — life in His presence. Even when Israel falls into rebellion, we witness repentance, covenant renewal, and divine mercy. The book culminates with the construction of the tabernacle and the descent of the cloud, the visible sign of God's glorious presence.
In Exodus, we see the foundations of Israel's identity: a people redeemed, covenanted, instructed, and indwelt by God. For Catholics, the book speaks not only of ancient history but of the enduring pattern of salvation: God delivers, God binds Himself to His people, God teaches, and God remains with them.
