2) The Eucharist ("You will see the Levites (deacons) bringing the loaves and a cup of wine, and placing them on the table. So long as the prayers and invocations have not yet been made,it is mere bread and a mere cup. But when the great and wonderous prayers have been recited, then the bread becomes the body and the cup the blood of our Lord Jesus Christ....When the great prayers and holy supplications are sent up, the Word descends on the bread and the cup, and it becomes His body." Athanasius,Sermon to the Newly Baptized,PG 26,1325(ante A.D. 373))
3) Mary, Queen of Heaven (It becomes you to be mindful of us, as you stand near him who granted you all graces, for you are the Mother of God and our Queen. Help us for the sake of the King, the Lord God and Master who was born of you. For this reason, you are called full of grace. Remember us, most holy Virgin, and bestow on us gifts from the riches of your graces, Virgin full of graces.)
How do we know which of Athanasius points are in error if any? I can take his first statement that the Scripture is all sufficient for us and validate the Eucharist and Mary, Queen of Heaven from the first premise. While there may be a limited case made for the Eucharist from scripture there is certainly no place in scripture for Mary being the Queen of Heaven. Consequently it isnt difficult to reject Athanasius 2nd and 3rd premise based upon his belief that we will know heretical doctrine by the word of God.
OTOH, you will have an impossible task of denying Athanasius view on the Divine word and supplementing them with traditions of the Church. He doesnt say that. Also to validate the Eucharist or Mary, Queen of Heaven with no scriptural support for the latter goes against what Athanasius states.
Well, Athanasius would argue that #2 and #3 are in scripture. As would the Orthodox, Catholics, and even Martin Luther.
1) Scripture is sufficient for all things (Now one might write at great length concerning these things, if one desired to go rate details respecting them; for the impiety and perverseness of heresies will appear to be manifold and various, and the craft of the deceivers to be very terrible. But since holy Scripture is of all things most sufficient for us, therefore recommending to those who desire to know more of these matters, to read the Divine word, I now hasten to set before you that which most claims attention, and for the sake of which principally I have written these things." (Athanasius, To the Bishops of Egypt, Ch 1, 4)
When the Church Fathers, including St. Athanasius, affirms the sufficiency of Scripture, they do not exclude, but SUPPOSE Tradition! For example, after St. Athanasius says "The Sacred Scriptures are sufficient to indicate the Faith in Christ", he adds "There are many books of our teachers which, if any one will read, he will in some manner understand the interpretation of the Scriptures and might know what he desires" (Athanasius, Orat. C. Gent., N. 1)
When Vincent of Lerin states "the canon of Scripture is perfect and is abundandtly sufficient to itself and to anything else", he adds that the Faith must be safeguarded, "first by Law of Divine Authority (Scriptures) and then by the Tradition of the Catholic Church". (Commonit., CC. I-II). He declares the reason for this double security in his famous sentence "because not all men accept the same sense of Sacred Scriptures, on account of their loftiness...hence, it is most necessary, on account of so many errors, that the line of prophetic and apostolic interpretation be drawn according to the rule of the ecclesiastical and Catholic sense" (Commonit. C. II).
The statements of the Fathers are therefore different then what you are trying to prove - that the Scriptures contain all that is necessary for salvation. The Fathers have always minded the Apostolic Succession, whose teaching and understanding is to be the course and rule in INTERPRETATION of Scriptures. They DO NOT separate the Scriptures from Tradition. Therefore, not all truths are clear from Scripture alone. What is clear is not clear enough to all the faithful. Proof of this is the Real Presence of the Eucharist - "clearly" stated in Scripture, but not believed by many Protestants of who read the Scriptures.
Nothing the Fathers say about Scripture excludes the Tradition of the Church, as it chronolicially and theologically PRECEDED Scripture.
Regards