זוהר שמות — דף קלב ע”ב

The secret of the Alef-Tav Beth-Shin letters encompasses the twenty-two letters, which are the crown of the thirty-two paths. The Name of seventy-two crowns the lower Merkava and ascends and descends to draw goodness below. The Name of forty-two crowns the upper Merkava and ascends without descending. The Shabbat praise El Adon uses the letters of seventy-two in twenty-two words, the secret of the twenty-two letters, so that Knesset Israel can ascend through this praise.