Said the Soul - My desire and will is to become settled regarding some items from among those about which it is said (Deuteronomy 4:39) "...and lay upon your heart that HaShem is the G-d...", behold they are among the essentials of our faith that every man must seek after knowing them, to the degree that he can grasp:ּ
The Soul's Desire to Know That HaShem Is God
Da'at Tevunot 1:1