He causeth the grass to grow for the cattle, and herb for the service of man: that he may bring forth food out of the earth;
Psalm 104:14 KJV
Isa 40:6 tells us that grass = flesh. 1 Cor 9:9-10 showed us that when God spoke of muzzling ox/cattle, it was spoke in reference to us. God providing grass for the cattle is symbolic language to say, God provides for the fleshy needs of man.
Herb however is for the spirit man. Examine the words of Christ (Matt 13:31-32). He spoke of a seed that was “the least of all seeds” when planted in the earth, but when it is grown, it’s the greatest among herbs.
That seed is Christ/the kingdom of God which is planted the hearts of men. When the seed was first planted, it was “least” compared to all the other “seeds” that filled our mind, but when it is grown, Jesus said that it becomes the greatest i.e. there will be no room in our hearts for any “worldly seed” to grow.
But before the herb can come forth, and become a source of food that the hungry, the spiritually destitute can eat, the seed must be watered with the of God’s word.
Hebrews 6:7 For the earth which drinketh in the rain that cometh oft upon it, and bringeth forth herbs meet for them by whom it is dressed, receiveth blessing from God:
Therefore, the herb for the service of man, is the seed of the word of God (Jesus) sown in us, watered and grown into a tree that provides food for the spiritually hungry.