Paths of Light in Isaiah: From the diachronic to the synchronic approach

The Book of Isaiah has been the classic example for historical-critical exegesis in proving the necessity of a diachronic study. Indeed, we can easily point to the well-known difficulty that Isaiah, while living in the 8th century BC, spoke about Cyrus, the King of Persia from the 6th century BC. Thus, literary criticism has been applied to the book as an instrument to trace the diversity of theologies, literary genres, cultural and political contexts, spanning from the 8th to at least the 4th century.

The first studies tended to concentrate on the biography of Isaiah and admittedly had a certain historicist bias. One was looking for the ipsissima verba of the prophet from the 8th century, while the text considered to be more recent and hence ‘not-original’ did not merit the same attention. It is because of the internal development of the historical-critical method itself that gradually the more recent editorial stages became the center of scholarly attention. Indeed, to explain these stages means to understand what is most fundamental: what is the central message, not of a single passage, but of the whole book? Synchronic approaches are therefore not in opposition to the historical method, but rather resulted from the growth of the method itself.

Quest for Unity

Anyone who has toiled trying to grasp the unity of the book will have experienced a great deal of frustration. The shifts of the speakers, themes, and literary forms are abrupt and often quite bewildering. The Book of Isaiah is definitely not following a linear way of thinking, nor developing arguments in any straightforward direction. The reader stands before a thicket, or rather a forest, and hesitates which path to choose.


Nevertheless, the book itself proposes many paths. One may begin mapping this land by following any chosen theme (e.g. kingship). If it appears often enough, the reader will be able to grasp the different contexts (positive, negative) or different subjects involved (God, human king, Messiah?, the people).

Finally, if the theme is well chosen, it will allow him to cross through all the book, thus experiencing something of this landscape and approaching the main question: why was it written? Or at least, why is it written like that? What is its message?

The choice of the right path in this quest is crucial. The choice of a single word is too narrow and limiting. One needs to refer to some reality that is common, flexible and meaningful. Preferable candidates seem to be symbols sensu stricto; i.e. universal and archetypal realities, which through what is visible connect to invisible realities. This essential quality is particularly useful in comprehending a work that is both poetry and theology. Since Isaiah invites us, “Come, let us walk in the light!” (Is 2:5), let us follow the light.


Studying the symbol of light in a book means precisely dealing with the linguistic expressions based on this material reality. Nouns and verbs associated with the sematic eld of light, as well as the metaphors of light become the rst subject of the study, together with the pericopes where they occur.

This brief introduction is not a place where all the passages can mentioned. Let me just indicate some conclusions from Is 2.

Light appears as a metaphor of knowledge. In the Scriptures knowledge is never purely speculative; it always conditions ethical behaviour. The already mentioned text of Is 2:5 speaks about the “light of Yhwh” in a parallel to Teaching, i.e. Torah. Nevertheless,in this very first verse one immediately understands that a single explanation is reductive, incomplete, and hence false. Does light stand for the moral law, the written Torah, ethical behaviour, or perhaps Yhwh Himself ?

Moreover, we encounter this invitation to walk in the light in the context of speaking about the last days. It is therefore the light of the last day, when the world is transformed and God recognised by all the nations. What conclusions can one deduce from such a cluster of ideas? Since light is indeed a symbol, it cannot be pinned down just to one single abstract notion, instead its very function is to reveal the necessary connections between diverse realities. One “walking in the light of Yhwh” already participates in the wonders of the last days. Is 2:5 functions both as a promise and an exhortation. If I the reader follow the light, that is if I follow the Teaching, continue reading this book, the eschatological victory is at hand.

From the diachronic perspective it is notable how the motif of light, since it crosses so many different cultures, makes it possible to juxtapose texts belonging to seemingly very distant traditions. Is 2:5-21 is a poem glorifying a day of royal victory and has parallels in the Neo-Assyrian literature. It is often the very presence of the glory of the divine king that made the enemies hide in the darkness. This mythological Near-Eastern topos of the victorious light is in Is 2 placed together with an eschatological vision and an ethical light.

It is up to the reader to interpret this juxtaposition and draw the right conclusions. There is a war going on in which the light is victorious. “Walking in the light of Yhwh,” therefore, means participating in His victory. Ethics and the study of the word are put together with military victory, in all its seriousness and finality. The mythological motifs are elevated into the eschatological, apocalyptical, and universal perspective.


Light appears to be a means through which the unity of the Book is assured. It allows us to make typological connections between myth, history, and eschatology. Since the symbols are universal they remain productive and are a preferable point around which to compose a unity from the texts belonging to such distant times.

The symbol of light has the capacity to make into one realities that could otherwise seem quite distant, like ethics and military victory. Last but not least, because light means also the word, it serves to create a self-referencing clue. This is the way in which the Book of Isaiah speaks about reading of the Book of Isaiah itself! Its function is nothing less than existentially involving the reader. He will gradually discover that this book is not about some distant past or distant future. Instead, exactly while he is reading this very book, he is reading about himself reading the book, about himself participating in the light and confronting the darkness. The power of the symbol is not just in the information it transmits, but in the things it does to the person who is exposed to it.

Fr. Łukasz Popko, o.p.