Sicha – RaMbaM / Alter Rebbe / VaAira (16)

Likutei Sichos – Vol 26 p 26 ff The Vow of Reb Chayim Vital and the RaMbaM limit who can learn their sefer, but it also allows, Jews for whom this is life and death (spiritually) to learn despite their deficiencies and use the Sefer to achieve a state of deservedness. Page 36-7.