Why? Why would God love me? That is an interesting, and fair question. It is natural for us, due to our sin, to distrust the intentions of any good toward us; that is the reason that in any relationship, we would like to have at least some of the control, over the reasons that relationship exist in the first place.
But what about God? This passage is clear: we are adopted because He is able to love, and as a way to celebrate His grace… nothing we can control