“It corresponds to the sefirah of the divine Mercy, or tifereth. The lowest sefirah, on the other hand, contains, by virtue of its correspondence to the action of divine judgment in the world, the Oral Torah, which is black fire burning upon an underlayer of white fire. “But the form of the letters is without vowels and is only potentially engraved in this black fire, which is like ink [on white parchment].” In the white fire itself the forms of the letter still do not actually appear, and where they do so we are already (in the symbolism of the black fire) in the domain of the Oral Torah.
“ … And thus the Written Torah cannot adopt corporeal form, except through the power of the Oral Torah; that is, that the former cannot be truly understood without the latter, just as the mode of divine Mercy can only be grasped and perceived through the mode of Judgment. And the figures of color, gawwanim, of black, which are those of Judgment, rise up and spread out over the configurations of white, which are those of Mercy, like the light of the coal. For the power of the colored configuration of the flames prevails until the light of the coal can no longer be perceived at all because of the excess of flames covering it.”
The simile of the coal and its flames is the same as that employed by Isaac so often in his commentary on Yesirah. The mystical Written Torah is still hidden, as it were, under the invisible form of the white light represented by the parchment of the Torah scroll and is in no way perceptible to the ordinary eye.
It is only when the mystical lights, in the play of flames, sometimes veer away from one another that they offer a momentary glimpse of the white light or the sphere of divine Mercy. At such moments, “many a prophet” can “snatch, by means of the ‘crown of royalty,’ [the last sefirah, accessible to their contemplation] something of this mystical splendor, each according to the spiritual degree of which he is worthy.” But this can be no more than a momentary intuition.
A truly lasting contemplation of this hidden form of the white light is as inconceivable as that of the sun by a terrestrial eye. Only Moses, the master of all the prophets, could attain a continuous contemplation of this “luminous mirror” and by virtue of his prophetic rank enter into spiritual communication with it.
The language of this symbolism is identical to that found in other of Isaac’s fragments. Hidden behind mystical symbols, we find a conception according to which there simply is no Written Torah within reach of the ordinary mortal.
Everything we call by that name has already passed through the mediation of the Oral Torah. The Torah apprehensible to man is not the hidden form in the white light but precisely the obscure light that already had adopted definite forms and determinations and that thereby designates the quality of divine Sternness, the quality of Judgment.
The Torah scroll itself symbolizes that. The ink and the parchment form a unity. But the element rendered visible by the ink is the blackness, the “obscure mirror” of the Oral Torah; the true secret of the Written Torah, which embraces everything, is contained in the signs, still not visible, of the white parchment.
In a word, there is only an Oral Torah, and the concept of a Written Torah has its place, in the final analysis, in the mystical domain, the sphere accessible only to the prophets. Therefore, here, at the very beginning of the historical appearance of the Kabbalah in the West, we have a thesis whose mystical radicalism can hardly be surpassed and was in fact not surpassed in the entire history of the Kabbalah.
It proves, more than anything else we know of him, that Isaac was a genuine esotericist. Isaac’s fragment fell into oblivion, but his thesis was taken up and elaborated more than once in the history of the Kabbalah, at times in much less veiled language.”
Gershom Scholem, Origins of the Kabbalah, pp. 288-9.