The Hazak[1] we say after completing the series means that the completion should give us strength to complete all the degrees. As the body has 248 organs and 365 tendons, the soul, too, has 613, which are the channels of the soul by which the bounty extends. And these channels are opened through the Torah. As long as not all of them have been opened, even if a deficiency appears in a particular degree, the particular degree is included in the whole.
Thus, if an element is missing from the whole, that same discernment is missing from the individuals, too, and they gradually incarnate by the order of degrees. And when they are all completed, this will be the end of correction. Prior to that, they will emerge and become corrected one by one.
Now we can understand what our sages said, “the Torah preceded the world.” This means that before the limitation of the world appeared, the Torah had already been there.
And how could it then shine within the world, which is a boundary? Rather, the Torah shines by way of one after the other. And when all the discernments are completed, one must leave this world, since he has harvested all the discernments of the Torah. Therefore, each ending should give us strengthening to continue further. And the five books of Torah correspond to the seven Sefirot, which are essentially five, since Yesod and Malchut are not the essence, only included.