Irenaeus was an apologist defending the Christian faith against the Gnostic heresies writing 5 books (Against Heresies) dealing with them. He also wrote a book Demonstration of the Apostolic Preaching, describing Christian teaching. All of these works are available to us today. In Against Heresies Book 3 (circa 180), Irenaeus describes how the gospel message was handed down from the apostles first through preaching, then by writing the Scriptures all with the power of the Holy Spirit.
From this passage we learn the following regarding the Gospel of Mark:
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. For it is unlawful to assert that they preached before they possessed “perfect knowledge,” as some do even venture to say, boasting themselves as improvers of the apostles. For, after our Lord rose from the dead, [the apostles] were invested with power from on high when the Holy Spirit came down [upon them], were filled from all [His gifts], and had perfect knowledge: they departed to the ends of the earth, preaching the glad tidings of the good things [sent] from God to us, and proclaiming the peace of heaven to men, who indeed do all equally and individually possess the Gospel of God. Matthew also issued a written Gospel among the Hebrews in their own dialect, while Peter and Paul were preaching at Rome, and laying the foundations of the Church. After their departure, Mark, the disciple and interpreter of Peter, did also hand down to us in writing what had been preached by Peter. Luke also, the companion of Paul, recorded in a book the Gospel preached by him. Afterwards, John, the disciple of the Lord, who also had leaned upon His breast, did himself publish a Gospel during his residence at Ephesus in Asia.
(Ad Haer 3.1.1)
- Mark the disciple of Peter wrote what Peter preached.
- Mark was enabled by the power of the Holy Spirit.
- Mark wrote after Peter and Paul were martyred in Rome.
- The Gospel of Matthew was written while Peter and Paul were preaching, and therefore was written before the Gospel of Mark.
And as he went out of the temple, one of his disciples saith unto him, Master, see what manner of stones and what buildings are here! And Jesus answering said unto him, Seest thou these great buildings? there shall not be left one stone upon another, that shall not be thrown down. And as he sat upon the mount of Olives over against the temple, Peter and James and John and Andrew asked him privately, Tell us, when shall these things be? and what shall be the sign when all these things shall be fulfilled?(Mark 13:1-4 KJV)It is strongly argued (and I have to agree) that Mark would certainly have mentioned the fulfillment of the prophecy here if it had already occurred.
That is all for tonight...
Edit: added link highlighting Irenaeus knew Polycarp in his youth.