2 Chronicles 28:3 vs Genesis 22:2 How is the contradiction explained between 2 Chronicles 28:3 and Genesis 22:2 in the protestant tradition?

Genesis 22:2 NIV


  Then God said, “Take your son, your only son, whom you
  love—Isaac—and go to the region of Moriah. Sacrifice him there as a
  burnt offering on a mountain I will show you.”


2 Chronicles 28:3 NIV


  He burned sacrifices in the Valley of Ben Hinnom and sacrificed his
  children in the fire, engaging in the detestable practices of the
  nations the LORD had driven out before the Israelites.
There's no contradiction. 

Keep in mind that, while God asked Abraham to sacrifice Isaac, he had absolutely no intention of letting him go through with it.  He did it in order to show that he would provide a (quite literal) scapegoat.  He would provide a replacement for Isaac on the altar.  This was meant as something to predict what Christ would do on the cross for us.  And, he did it in a world that existed before the Mosaic law.  Again, he gave Abraham a command that didn't contradict any of his previous commands, and expected him to follow through with it, though God had other plans. 

In 2 Chronicles 28:3, the practices were detestable, because by that time, God had given the Israelites the Mosaic law, and his prescription regarding how they were to worship Him.  By sacrificing children, they were going outside the Mosaic law, which was given after Abraham.

It's pretty much the same answer as this question.