In order for G-dliness to be properly drawn down through Torah and mitzvot, it is first necessary that there be the “elevation of mayin nukvin,” emanating from man’s love of G-d to the degree that he is ready to forgo everything for His sake.With this, the Alter Rebbe concludes the theme beginning in ch. 46 regarding the love likened to “water mirroring the image of a face” and concerning which he had said that the Shema and its introductory blessings are especially effective in awakening it.