“We have learned from none others the plan of our salvation, than from those through whom the Gospel has come down to us, which they did at one time proclaim in public, and, at a later period, by the will of God, handed down to us in the Scriptures, to be the ground and pillar of our faith” (Against Heretics, 3.1.1).Two simple things to notice. First, observe how Irenaeus uses the technical phrase of the body of tradition being passed on, “handed down to us in Scripture”. The Scripture is the “handed down” tradition.
Second, this follows the pattern of Paul himself, who wrote, “Therefore, brethren, stand fast and hold the traditions which you were taught, whether by word or our epistle” (2 Thessalonians 2.15). Not only are they (by word or by letter) authoritatively equivalent, but the “whether…or…” shows that they have corresponding content.
For Irenaeus, the tradition scripted in sacred Scripture was the fitting weapon and dependable tool against those Gnostics who alleged “that the truth was not delivered by means of written documents, but viva voce (living voice)” (3.2.1).
“Almighty God, who did uphold Your servant Irenaeus with strength to maintain the truth against every wind of vain doctrine: we beseech You to keep us steadfast in Your true religion, that we may walk in constancy and in peace the way that leads to eternal life; through Jesus Christ our Lord. Amen.”