Act 1:21-22 Wherefore of these men which have companied with us all the time that the Lord Jesus went in and out among us, (22) Beginning from the baptism of John, unto that same day that he was taken up from us, must one be ordained to be a witness with us of his resurrection.That is stated as a requirement, not a "nice to have." Even Paul was required to have met the resurrected Jesus personally on the road to Damascus, else he would not be qualified for the apostolic office. See also Acts 22:14-15 and 1 Corinthians 9:1.
Mar 3:13-15 And he goeth up into a mountain, and calleth unto him whom he would: and they came unto him. (14) And he ordained twelve, that they should be with him, and that he might send them forth to preach, (15) And to have power to heal sicknesses, and to cast out devils:Finally, selection to the apostolic office entailed a unique capacity for demonstration of divine power through miracles:
Luk 9:1-2 Then he called his twelve disciples together, and gave them power and authority over all devils, and to cure diseases. (2) And he sent them to preach the kingdom of God, and to heal the sick.Now, I have some odd people for nextdoor neighbors. They think they are apostles. Seriously. They have a church. They blow shofars. It's a latter rain cult, right on my doorstep. These same "apostles" were systematically disposing of construction garbage that was getting onto my property and damaging my tires. By the grace of God they were forced to withdraw. But needless to say these individuals, no matter how impressed they are with their own sense of apostolic entitlement, have not impressed me with their apostolic qualifications, at least not according to the three points listed above.
This is the vital point. In a contest of interpretations, which one wins? Athanasius appeals to an authority other than HIS own or the mere words of Scripture. I will snip a quote of his from
"For not only in outward form did those wicked men dissemble, putting on as the Lord says sheep's clothing, and appearing like unto whited sepulchres; but they took those divine words in their mouth, while they inwardly cherished evil intentions. And the first to put on this appearance was the serpent, the inventor of wickedness from the beginning-the devil,-who, in disguise, conversed with Eve, and forthwith deceived her. But after him and with him are all inventors of unlawful heresies, who indeed refer to the Scriptures, but do not hold such opinions as the saints [meaning orthodox saints or Fathers -- see article at top] have handed down, and receiving them as the traditions of men, err, because they do not rightly know them nor their power. Therefore Paul justly praises the Corinthians, because their opinions were in accordance with his traditions. And the Lord most righteously reproved the Jews, saying, 'Wherefore do ye also transgress the commandments of God on account of your traditions.' For they changed the commandments they received from God after their own understanding, preferring to observe the traditions of men. And about these, a little after, the blessed Paul again gave directions to the Galatians who were in danger thereof, writing to them, 'If any man preach to you aught else than that ye have received, let him be accursed.'" (Festal Letter 2.6)
He asserts that tradition informs and supports his interpretation. The Council ratifies it and from here forward the line is clearly drawn. Orthodoxy is defined. Subsequent councils could then require Bishops to affirm Nicean orthodoxy.
Holding that Athanasius relied solely on Scripture must be understood in the context of what his other writings show HIS understanding to be. Athanasius surely held also with the transmission of apostolic authority, and I expect he would have dealt with your nutty neighbors in a couple of short paragraphs. But, thats for further discussion.