Adam Clarke on Genesis 2:15

Put him into the garden - to dress it, and to keep it - Horticulture, or gardening, is the first kind of employment on record, and that in which man was engaged while in a state of perfection and innocence. Though the garden may be supposed to produce all things spontaneously, as the whole vegetable surface of the earth certainly did at the creation, yet dressing and tilling were afterwards necessary to maintain the different kinds of plants and vegetables in their perfection, and to repress luxuriance. Even in a state of innocence we cannot conceive it possible that man could have been happy if inactive. God gave him work to do, and his employment contributed to his happiness; for the structure of his body, as well as of his mind, plainly proves that he was never intended for a merely contemplative life.