Have you ever heard the parent of a troublemaking son or daughter dodge responsibility with the protest, "No child of mine ...", or disown that same little one in a crisis when the other parent appears — "your child has really done it now ..."?
Parents (myself included) are often quick to expect perfection from their children, and are shocked when it doesn't appear .... "You should know better!", we say. Yet, far from having the right to pose as mature and sinless adults (whether we are parents or not), we, too, are often merely disobedient children in the eyes of God.
As Paul writes to the Roman church, "All have turned away from God; they have all gone wrong; no one does what is right, not even one." Paul isn't talking about the Roman church's child care program here; he's talking about the grown-ups. But God proves Himself to be a good parent: He doesn't hide the fact that we belong to Him. He doesn't disown us at the first sign of childish rebellion ... or the second, or the third, or ever, really. On the contrary: even while we were lost in our sin, Scripture says, God showed that He was not willing to lose a single one of us. He sent Christ to die in our place while we were still sinners.
Jesus took our place on the cross, and experienced the death and separation from God that we deserved. God didn't wait for us to come to our senses, or to prove that we were going to "behave" for the duration. This gift, this forgiveness, is not a reward for good behavior. It is free and undeserved. Even so, God says, "You are worthy of this gift because you belong to Me. I am your father; you are My child. I love you, and I am not willing to lose you."