Monday Sh'vat 19 5703
Chumash: Yitro, Sheini with Rashi.
Tehillim: 90-96.
Tanya: Hence they are (p. 93)...body to a soul. (p. 95).
The first positive mitzva is, in the words of Rambam, [1] "To know that there is a First Being, who caused the existence of all beings...The knowledge of this principle is a positive command, as it is said, I am the Eternal your G-d."
This is a Mitzva relating to mind and intellect. *
True, every one of Israel believes in G-d with a simple faith, and his heart is whole with G-d; still it is the duty of the mind and intellect to bring this faith to a level of knowledge and comprehension.
This is the meaning of "To know that there is a First Being;" the Mitzva specifies comprehension and intellectual grasp, as written in Torah: "Know the G-d of your father and serve Him with a whole heart" [2] and it is also written, "know this day etc." [3]
Notes:
Maimonides: Mishneh Torah, Yesodei haTorah 1:1.
Divrei Hayamim I, 28:9.
4. Devarim 4:9.
See "On Learning Chassidus" (Kehot) p. 33.