Nefesh HaChayim, An Introduction by the Author's Son

29In this paragraph and the next Reb Itzele explains how Rav Chayyim permitted himself to include direct quotes from the Zohar, the Ariza”l’s writings and other sources not normally permitted to be taught in public.Annotation: And maybe this was the intention of the verse (Yeshayahu 50:4): “God-ADN”Y God-YHV”H has granted me a tongue able to teach… He arouses my ear to be able to hear what the students perceive.” Meaning that God-H’ (blessed be His name) gave me the ability to teach mussar to others. And He (blessed be His name) aroused his ear so that he also could teach himself mussar, like the lessons that he teaches to others.