Nefesh HaChayim, Reb Itzele's Long Annotation

(And the teaching about the explanation of the letters512The three letters of the word tzellem—tzadiq, lamed and mem is: tzadiq is first, about action. After that lamed is the aspect of the surrounding intellect in the brains. And after that the mem is the aspect of the nehtzakh/hod/y’sode and malkhoot of beena—for “only if you call out to understanding513Heb.: kee eim la-beena tikra—The s’feera of beena is also known as the pahrtzoof of eema (“Mother”)” (Mishlei 2:3). This is the context for “age of forty to understanding” and the forty days for the formation of the fetus514The forty being the four s’feerote. Their being in the world of Y’tzeera supplies the multiplier of ten.. And as is known, the closed form of the mem at the end of the word eim515Eim (spelled alef, mem) is Hebrew for “mother”. The form of the letter mem sofeet (the letter mem when used at the end of a word) is closed. is because that when she516Beena is pregnant she is sealed.)