I grew up in Pennsylvania: the keystone state. I guess that name made sense at some point, Pennsylvania was sort of the middle of the colonies, it was the seat of power ahead of the Revolutionary War. Whatever, I only need you to think about the idea of a keystone so that I can make the following point.
The keystone text for understanding Genesis and Mark this Sunday morning is a line we will hear read twice on Sunday morning. Its original context is found in Psalm 8 and it gets quoted by the author of Hebrews in his treatment of Angels in chapter 2, but I think it is the key for preaching God’s view on marriage, divorce, and the place of children.
“What is man that you should be mindful of him?” (Ps 8.5a, BCP) or for a more gender neutral reading, the NRSV translates Hebrews 2.6b as “What are human beings that you are mindful of them…?”
The answer is, of course, that human beings are the only part of God’s creation that were made in the imago dei. We bear within and upon us the image of God. We are chief stewards, the managers of creation. We are, for all intents and purposes, God’s best and most beloved handiwork, and because of this, God is mindful of us.
And because God is mindful of us, the things that happen to us matter to him. And because these things matter to God, the pain we feel is felt by God. And because God feels our pain, Jesus takes a hard line on divorce and exploitation.
God cares enough about us to bring a hard line on the choices we make.
Draughting Theology 
Thanks for drawing my attention to that verse. I think there is some real irony (almost sarcasm) in these lessons. The Genesis passage presents an ideal based on the creation-event, and the Pharisees seem to miss that point, which Jesus highlights with his over-the-top teaching on divorce and remarriage. What I’ve been hearing him say is, “Come on, guys! Don’t you know that the divine-human relationship isn’t based on questions like yours?” And I think the verse you highlight is a wonderful reminder. “What is man that you should be mindful of him?” Exactly. But history shows us just how mindful of us God really is because, as you point out, he made us in his image and loves us. Thanks for the lead.
Steve, thanks to my science / math education, I often think of humans as a projection of God onto three dimensions. Imagine how we cast a shadow onto two dimensions, realize that God exists beyond three dimensions, and think of the implications!