They asked our Rebbi the Gra: How is the mitzvah of bitachon in HaKadosh Baruch Hu [kept]? And he said: David HaMelech, alav hashalom, already explained it to us (Tehillim 131:2): “I have truly calmed and quieted my soul, like a nursing child with his mother; my soul within me is like a nursing child.” This means: like the nursing child who sucks at his mother’s breasts; when he has nursed until he is full, he does not worry or take to heart whether he will have something to nurse after some hours, when he is hungry. My soul within me is like this child: I do not worry at all about what will be after an hour, or tomorrow. And this too is what is written (Tehillim 22:9–11): “Roll [your burden] onto Hashem; He will deliver him, He will rescue him, for He desires him. For You drew me out of the womb; You made me secure on my mother’s breasts. Upon You I was cast from birth; from my mother’s womb You have been my G-d.”