And Pharisees came up and in order to test him asked, “Is it lawful for a man to divorce his wife?” He answered them, “What did Moses command you?” They said, “Moses allowed a man to write a certificate of divorce and to send her away.” And Jesus said to them, “Because of your hardness of heart he wrote you this commandment. But from the beginning of creation, ‘God made them male and female.’” (Mark 10:2–6, ESV)

“Hardness of heart” in the ESV translates a single word in the Greek: σκληροκαρδία [sklērokardía], sklero = hard and kardia = heart.

Notice that Jesus doesn’t say that Moses allowed a certificate of divorce because of “their” [those guys in Moses’ time] sklerokardia, but because of “your” [you guys now! sklerokarkdia].  This is revealing.  Men had not changed since the time of Moses.  They had hard hearts then, Jesus says that in the same way, you men now have hard hearts.  If he were here today he would say the same thing to us.

The Message paraphrases vs. 5 like this:

Jesus said, “Moses wrote this command only as a concession to your hardhearted ways.” (Mark 10:5, The Message)

God understands us completely.  He totally recognized that, even though he had instituted the institution of marriage, and even though he meant it to be until death, that men had this odd disease of sklerokardia and that he needed to do something in light of that.  He did not want divorce, yet he allowed it as a concession to your/their/our hard hearts.

Here’s the thing:  Our sklerokardia doesn’t just show up in our attitudes toward the possibility of divorce.  It bubbles out through the cracks in our character in many places: in our desire to be comfortable and not have any problems, in our desire to have “perfect” kids, in our niggling selfishness that insists that we should be first in line and no one else, and in our lack of compassion for the needy.

The only antidote to our sklerokardia is to take on Jesus’ soft heart.  He did not suffer from sklerokardia and never will.  We take on Jesus’ heart through obedience day by day by day.