We are sons & daughters of the King. But it takes a while for the 'family resemblance' to show up. We are God's workmanship, but when we first start following Jesus, we look at our lives and think, "I don't work like the Bible says I should." God growing us toward His resemblance and toward working right is sanctification.
Here are a few fun quotes on sanctification & our responsibility in it (obedience) that I had jotted down but was unable to share in the sermon:
"The more often [man] feels without acting, the less he will be able ever to act, and, in the long run, the less he will be able to feel." - C.S. Lewis
"Only the devil has an answer for our moral difficulties, and he says, 'Keep on posing problems, and you will escape the necessity of obedience." - Dietrich Bonhoeffer
"Our sanctification does not depend as much on changing our activities as it does doing them for God rather than ourselves." - Brother Lawrence
"Holiness is not an experience; it is the re-integration of our character, the rebuilding of a ruin. It is a skilled labor, a long-term project, demanding everything God has given us for life and godliness." - Sinclair Ferguson
'My child,' 'my child,' When fathers say 'my child,'
'Tis easier to conceive the universe,
And life's transitions down the steps of law. - Elizabeth Barret Browning