The First Sefirah is Passed Over in Silence
“After the resurrection, the righteous and the average realize a new progress in their spiritual and moral perfection, one that takes them beyond everything they attained in their lives. By this adherence to the seven divine middoth, all will share perpetually in the gift of prophecy.
From a brief allusion of ibn Sahula (f. 34a), we can infer that on several occasions Isaac expressed his views on eschatological matters, in the context of which he may also have discussed the preparation for redemption by means of the purification of souls during their transmigrations.
In the extant texts, however, there is no clear statement on this subject, though on one occasion Isaac quotes a relevant passage from the Bahir, section 105.
Isaac of Acre states that in his commentary on Yesirah Isaac the Blind made a hidden allusion to the distinction between the migration of souls (gilgul) and the impregnation of souls (ibbur) as being two different things, but I have not been able to locate this allusion.
It should be clear from the foregoing that Isaac the Blind already had at his disposal a complete system of kabbalistic symbolism, partly inherited from tradition and partly elaborated by himself which he applied to a great variety of biblical and rabbinic subjects.
His epistle to Gerona, which has survived, offers a brief explanation of the last psalm, apparently in response to a question. The psalmist’s tenfold invitation to praise God is interpreted as an allusion to the ten sefiroth, though the first sefirah is passed over in silence, and Isaac counts downward beginning with hokhmah.
His mystical allusions in this epistle scarcely differ from the instructions he gives for the mystical kawwanoth at prayer; there too, he briefly describes the process by which the mystic first traverses the world of the sefiroth from below upward during the profession of the divine unity, the Shema’ Yisrael, and then, in his meditation on the word ‘ehad, “one!” completes and closes the circle of his kawwanah, from above downward.”
Gershom Scholem, Origins of the Kabbalah, pp. 308-9.