Frequently, Lutherans and Protestants, in general, will quote church fathers arguing that when they use the term Scriptures, they mean "Bible." Here are a few examples:
St. Athanasius-- The holy and inspired Scriptures are fully sufficient for the proclamation of the truth. (Against the Heathen, I:3)
St. Gregory of Nyssa--For we make Sacred Scripture the rule and the norm of every doctrine. Upon that we are obliged to fix our eyes, and we approve only whatever can be brought into harmony with the intent of these writings. (On the Soul and the Resurrection) and Let the inspired Scriptures then be our umpire, and the vote of truth will be given to those whose dogmas are found to agree with the Divine words. (On the Holy Trinity)
St. John Chrysostom--Regarding the things I say, I should supply even the proofs, so I will not seem to rely on my own opinions, but rather, prove them with Scripture, so that the matter will remain certain and steadfast. (Homily 8 On Repentance and the Church)
St. Cyril of Jerusalem--For concerning the divine and holy mysteries of the Faith, not even a casual statement must be delivered without the Holy Scriptures (Catechetical Lectures, IV:17)
These are some common "proof texts" from some of the Eastern Fathers about sola Scriptura. To a Protestant, the word "Bible" can be be used synonymously with Scripture. But what did Scripture mean for the early fathers? Did it mean Bible? It couldn't have been. First, the concept of the Bible was unknown to the early fathers. There wasn't even a codified "New Testament" before the 5th century or at least one that was agreed upon universally. (Also, the Gospels were kept in their own codex, which is still preserved in the Eastern Churches called the "Evangelion" and the letters of St. Paul and St. Peter and St. Jude and St. James and St. John were kept in another codex called the "Apostolos." During the Liturgy, the Gospel and Epistle are never read from a Bible but from the Evangelion and Apostolos, respectively.) Even when used in the New Testament, Scripture refers exclusively to the "Old Testament." In the Nicene Creed, the Symbol of Faith, when we confess secundum Scripturas or, in Greek, kata tas graphas, which mean "in accordance with the Scriptures" or "in fulfillment of the Scriptures" we are referring again to what is know as the Old Testament. And that is what the fathers quoted above mean by it, too.
But what did later fathers mean by Scripture? A New Testament had been codified by then. Did the terms Scriptura(e) or Graphi come to be synonymous linked with the term "Bible" maybe in the sixth century? Even if we assume that it did (and I'm not conceding that point), it refutes the notion of the Reformers that the doctrine of sola Scriptura, referring to both the Old and New Testaments as the foundation of all doctrine does not hold up to historical scrutiny. The Reformers and her modern heirs, frequently boast that their churches had returned to the church of the apostolic age. So, does Scripture mean both Old and New Testament by the middle of the first millennium? Very hard to even come to that conclusion.
What is the basic meaning of Scripture, Scriptura, Graphi? In Greek and Latin, it derives from the word meaning "writing." By the middle of the first millennium, there were many writings beyond just the Old and New Testament concerning the witness to the revelation of Christ. (Aside: Just to clarify, and I've said this many times. Word of God is a who not a what? The Word, the Logos is the God-Man (Theanthropos) Christ incarnate. The Scriptures are a WITNESS to Him who revealed Himself). This is from the introduction of a recent edition of St. Isaac the Syrian's Ascetical Homilies:
Saint Isaac very often writes about the reading of ‘Scripture’. In English this word has come to mean the Bible and nothing else. In Greek and Syriac, however, this is not the case. We may recall Saint Peter’s words, ‘For prophecy came not in old time by the will of man, but holy men of God spake as they were moved by the Holy Spirit’ (2 Peter 1:21). For the Church, ‘Scripture’ refers to the writings of all holy men who were moved by the Spirit: the Prophets, Apostles, and the holy Fathers. Therefore, by ‘Scripture’ Saint Isaac means both the Bible and the writings of the holy Fathers. On a few occasions it is evident from the context that he can only be speaking of the writings of the Fathers; here to avoid confusion, we have used ‘writing.' (emphasis mine; p. 573, published by HTM, 2011)Now, St. Isaac the Syrian was no innovator and he is not some minor figure in Orthodoxy (Aside: I love how certain Protestants demand that the Orthodox faithful name a church father who defends what the Orthodox believe and when such a father is produced, the Protestant retorts that such-and-such is a "minor" figure. Pr. McCain is particularly guilty of this). St. Isaac is a very crucial witness in Orthodox theology. Keep in mind that he lived and wrote in what is modern day Yemen. Though he held a Christology that was near Nestorian (name me one church father who was completely right on everything), it shows that such a tradition of thought with regards to how to identify the Scriptures as meaning Old/New Testament and the writings of the church fathers was widespread even past the oikoumene of the Eastern Roman Empire which had long lost any political or military hold on the Arabian peninsula.
Orthodox can hold to sola Scriptura, then provided that the meaning of Scriptura is not just Old and New Testaments. Not only would we include the writings of the holy fathers, but the decrees of the ecumenical councils, the liturgies of St. John Chrysostom, St. Basil the Great, St. Gregory the Dialogist and St. James and even icons as Scripture (icons are "written" not painted). Of course, I doubt seriously that any Protestant would willingly expand the meaning of Scriptura to include all those other witnesses. Such is why Protestantism cannot be considered to be "catholic" nor the historic faith.
My thanks to Under the Dome for pointing me to this quote from the new edition of St. Isaac's homilies.