Part 12 · Chapter 154

But now we need the first Shema to draw those Mochin of midnight, and the second Shema to draw the other, higher Mochin. And this is the reason they instituted reciting these verses of "Shema Yisrael" and "Baruch Shem Kevod" of the order of the sacrifices, for one who does not follow the custom of the Vatikin.