"Tend" and "keep"—We might say "embellish" and "guard" or "add to" and "keep from deterioration." Anybody who has taken care of a piece of material equipment of some kind—a garden, a house, an automobile, clothing, it matters not—knows that one can embellish it, dress it, and that it takes work. It also takes work to maintain it, to guard it from falling into a state of disrepair.
God's real purpose here has something to do with the material things of life, but He is considering something much greater than that, something spiritual. He is indicating that spiritual things in our lives are also going to have to be embellished, added to, dressed, and they will have to be kept from deteriorating and guarded. There is work involved in those activities. Proper management, or dominion, over the things that God has put within the scope of our authority take work. So, both of these words indicate work.
John W. Ritenbaugh
Love's Greatest Challenges