Illuminates the Soul and the Eyes
Rav Avrohom of Slonim, mechaber of Yesod Ho’Avoda, writes in Be’er Avrohom (p. 335) that “the Zohar and the Ohr HaChaim illuminate a person’s soul and his eyes...till this day the Chassidim study the holy Ohr HaChaim’s commentary to the Torah on Thursday nights (Leil Shishi – Ohr LeYom Vov) and on Shabbos Kodesh at night.”
A More Appropriate Segula for our Generation Than the Zohar
Rav Menachem Nachum of Shtefanesht felt that studying the Ohr HaChaim HaKodosh was a more appropriate segula for our generation than the study of the Zohar, because as he explained, the Zohar illuminates the part of the soul called Neshoma, whereas the Ohr HaChaim illuminates those parts called Nefesh and Ruach. The part of the soul called Neshoma is so lofty that few individuals in our generation possess and attain that level at all, whereas all of us in this dor have a nefesh and ruach, making the Ohr HaChaim more fitting.
A Segula for Emuna Tehora
A delegation of Chassidim once approached Rav Yaakov Yosef of Skver seeking advice for a certain bochur who had sfeikos be’emuna – doubts and skepticism regarding his faith and belief. The Rebbe advised them to study with him the sefer Ohr HaChaim HaKodosh. When they asked him if they should focus on those essays that deal with Yiras Shomayim specifically, he explained that they should study with him the entire sefer from start to finish.