Contemporary English Version (CEV)
Adoption is a pretty wild idea. The child doesn't often have any say or control over the situation -- it's decided by the parents, who offer their love to a child they don't know, welcoming them into their family and forever changing their lives as they are interwoven into this new way of living.
We, too, are adopted by God. We who have been tainted by sin are adopted by God, who in the process of adopting us cleanses us from our sin. God does this out of his generous love, and our futures are forever transformed by this gracious act of God's love.
The light has come into the world to reveal this to us. The incarnation is amazing -- God puts on human flesh and becomes fully man so that we might know God fully. He is generous and loving and kind and patient, and we should be amazed that God chooses to lavish his love upon us.