Here's another phrase from Scripture that has always intrigued me: "a man after God's own heart," as in King David. Who wouldn't want to be described like that? But what do you do, or what do you have to be to be a person after God's own heart? I always thought it meant that David was living a life that made God's heart happy. Perhaps.
When an artist copies a painting done by someone else (usually someone the artist wants to emulate or learn from), he signs the painting "after" the artist. Like, "Julie Hanes after Claude Monet." Maybe to be a person after God's heart means that I am seeking to make my heart a replica of His.