Consider Polycarp: (ca. 69 – ca. 155)
With Clement of Rome and Ignatius of Antioch, Polycarp is regarded as one of three chief Apostolic Fathers. The sole surviving work attributed to his authorship is his Letter to the Philippians;
Polycarp’s Letter to the Philippians (often simply called To the Philippians) composed around 110 to 140 AD is described by Irenaeus as follows:
There is also a forceful epistle written by Polycarp to the Philippians, from which those who wish to do so, and are anxious about their salvation, can learn the character of his faith, and the preaching of the truth
In his letter to Philiipians: Chpter 12
supakoo.com/rick/PolycarpToPhilippians-2010-01-05.pdf
Note he uses the term Scriptures:
Note what New Testament books he is quoting or referencing…
Questions:
How did Polycarp know those letters were Scripture?
What Church degree or council had decided that by 140AD?
12
For I am confident that you are well versed in the
Scriptures, and nothing is hid from you; but to me this is not granted. Only, as it is said in these Scriptures,** “be angry but do not sin,”64** and “do not let the sun go down on your anger.”65 Blessed is the one who remembers this, and I believe that it is so with you. Now may God and the Father of our Lord Jesus Christ, and the eternal Priest himself, Jesus Christ, the Son of God, build you up in faith and truth, and in all gentleness, and without wrath, and in patience, and in longsuffering, and endurance, and purity, and may he give you a share and place with his saints, and to us with you, and to all under heaven who shall believe in our Lord and God Jesus Christ and in his Father who raised him from the dead. Pray for all the saints.66 Pray also for the kings, and for magistrates, and princes, and for those who persecute you and hate you,67
64 [XR] Eph 4.26, quoting Ps 4.5
65 [XR] Eph 4.26
66 [XR] 1Ti 2.1
67 [XR] Mt 5.44