Midras Mazmur 104:14: Shemot Rabbah, Sifrei Devarim & Midrash Tehillim

Rabbi Simon began in the name of Rabbi Eliezer: “The Lord is the God of hosts [tzevaot], the Lord is His designation” (Hosea 12:6), He carries out His will [tzivyono] upon His creations. Alternatively, “the God of hosts,” he carries out His will upon His angels. When He wishes, He makes them sit, as it is stated: “An angel of God came and sat beneath the terebinth” (Judges 6:11). At times, He makes them stand, as it is stated: “Seraphs standing” (Isaiah 6:2). And it is written: “I will grant you movement among those standing” (Zechariah 3:7).³The reference is to angels standing. At times He makes them in the guise of women, as it is stated: “Behold, two women emerged and wind was in their wings” (Zechariah 5:9), and at times, in the guise of men, as it is stated: “Behold three men” (Genesis 18:2). At times He makes them into winds, as it is stated: “He renders His angels winds” (Psalms 104:4), and at times, fire, as it is stated: “Flaming fires His servants” (Psalms 104:4).
Alternatively, “the Lord is the God of hosts [tzevaot],” He carries out His will [tzivyono] upon the world. When He wished, He produced bread from the earth, as it is stated: “To produce bread from the earth” (Psalms 104:14). He brought down water from the heavens, as it is stated: “From the rain of the heavens, it drinks water” (Deuteronomy 11:11). When He wished, He raised water from the earth, as it is stated: “Rise, well, call to it” (Numbers 21:17), and He brought down manna from the heavens, as it is stated: “Behold, I will rain down bread for you from the heavens.”

Variantly: "And I shall give grass in your field to your field": This is flax. And thus is it written (Psalms 104:14) He makes flax sprout for the beast, and grass for the labor of man."

Growing grass. Rabbi Yaakov bar Acha, Rabbi Nechemia, and the Rabbis [dispute this]. Rabbi Nechemia sayso : "See the language that the Sages established in the blessing of Hamotzi, for he brought bread from the ground." The Rabbis say that this refers to the future [in the days of the messiah] when he will bring forth finished loaves of bread from the ground, as it says, "Let loaves of bread be in the ground" (Psalms 72:16)[See Rashi on the Psalm there as to how the Peshat differs from the translation of the Sages]. "Bread for the eater shall be produced from the earth" (Isaiah 55:10). Rabbi Yitzchak said: "We find three places where bread is mentioned in the context of sustenance: with Abraham, as it is written, 'And I will fetch a morsel of bread, and you shall sustain your heart' (Genesis 18:5); with the Levite in Judges, as it is written, 'Sustain your heart with a morsel of bread' (Judges 19:5); and here, where it says, 'bread of the human heart shall sustain'."