The Structure and Protreptic Function of Thomas's Prologue to the Gospel of John

One of Thomas's most elegant prologues is certainly his prologue to his commentary on the Gospel of John, which is structured around the passage from Isaiah 6:1 that reads: "I saw the Lord seated on a throne high and lofty, and the whole earth was full of his majesty, and the things that were under him completely filled the temple [Vidi dominum sedentem super solium excelsum et elevatum, et plena erat omnis terra maiestate eius, et ea quae sub ipso erant, replebant templum]."¹ In what follows, I have attempted to set forth the essential elements of what I take to be the structure and function of this prologue.

We begin with an analysis of its mnemonic structure. This prologue, as with nearly all of Thomas's prologues, from his Sentences commentary on, uses the structure of the preaching style common at the time—what was called the sermo modernus style of preaching. As we examine each part of the prologue, we will also want to ask: "What was the purpose of this prologue?" To put this in Aristotelian terms, we might say: As we examine the formal elements of the prologue, we will also want to ask about its final cause. What was the prologue supposed to do for its readers or do to its readers?

I will be suggesting that, just as the structure of the prologue is very different from anything the reader will find in contemporary literature, so too our contemporary expectations about what a prologue should do are very different from those of Thomas Aquinas and his audience. Our expectations about appropriate material for a prologue have been conditioned in large part by nineteenth- and twentieth-century concerns about the importance of historical, literary, and intellectual context. Living as we do in the wake of the Freudian revolution, we have come to assume that the biography of the life of the author will somehow be revelatory of the text we are about to read. So too, living as we do in the wake of Hegel and his followers, we assume that a text must be understood in terms of its historical and intellectual context. And living as we do in the wake of the great advances in philological scholarship of the late-nineteenth and early-twentieth centuries, we have come to expect an introduction to tell us numerous details about the manuscript tradition of the text, as well as the status of various previous editions. Finally, if the text is what we generally describe as a "literary" one, contemporary literary scholarship has conditioned us to expect an introduction to compare our text's literary style with those written contemporaneously or those on which our author's text was based. These were not, I would suggest, for good or for ill, the expectations of Thomas's medieval audience. What those expectations were and the difference they made will be the subject of final section of this article.

Prologues and the Sermo Modernus Style

In a "modern sermon" of the sort that was common in Thomas's day, the preacher did not set out to comment on the opening biblical verse, called the thema of the sermon. Rather, the medieval preacher would use this verse as a mnemonic device to structure the message he wished to deliver. Thus, the first task for the preacher, after locating the right thema verse, was to divide it into three or four major parts, each of which he would then expand upon or "dilate" in the body of the sermon itself.²

Thomas divides the thema verse for this particular prologue, Isaiah 6:1, into three parts: (1) "I saw the Lord seated on a throne high and lofty"; (2) "the whole house was full of majesty"; and (3) "the things that were under completely filled the temple." In each phrase, there is a dominant image: in the first, "high and lofty" (excelsum et elevatum); in the second, "full" (plena); and in the third, "filled completely" (in Latin, replebant, from which we get the English...