We're pretty quick to say that Saul was a sinful man because he got faith so dramatically wrong. God told him exactly what to do, and he didn't do it. How much more self-centered and faithless can you get?
But what if Saul's faithlessness was actually an act of...faith?
This is where things get complicated.
Let's remind ourselves what we're talking about: we're talking about a scene in King Saul's (Old Testament) life where God led him into battle and told him to completely destroy everyone and everything, but Saul brought back quite a bit of booty, including livestock, to offer as a sacrifice to God. This is the point where Samuel informs him that because he is a wicked man, God has ripped the kingship right out of his hands and his entire family will die a horrible, powerless death because of it. The dynasty is over.
If Saul brought back all that good-looking, shiny, amazing stuff from his enemy because he wanted to keep it, like Achan, then I'd say that what we have here is a sin problem. If he was greedy about it, it's definitely a problem with his heart. If Saul thought to himself that God couldn't possibly want to destroy such good and beautiful things and that he must have misheard the instructions, then yes, we're in trouble.
But that wasn't where Saul's heart was. Saul's heart saw the good and beautiful things and wanted to give them deliberately to God. He wanted to make them sacrifices. He knew God's law so well that he knew what God desired. Saul looked at that livestock and immediately thought in his heart, "Man, this would make an aroma pleasing to the Lord!" And, well, if you can slaughter something at the altar, it certainly seems strange - by faith - to slaughter it in the field instead.
In fact, that's what God had told His people on the edge of the Promised Land. He told them He was going into the land with them and would make a place for His name and that from now on, everyone would have to come and make their sacrifices there. No longer could they just slaughter things at home or in the field; they had to bring them to God.
So what Saul is doing is actually an act of worship. Legitimately. It is the way that he understands the rules and regulations of God in general. It is the way his heart is wired to worship the Lord. He has in him this thing that understands what God desires, and the minute he raises his sword to make a slaughter in the field, something stops him. No. A slaughter like this should be done at the altar.
It's not because Saul so poorly understands God, then, that he commits this "sin," but precisely because he understands God so well. Because his sense of worship is so strong. Because his connection to the ritual of sacrifice is so strong.
Saul does what God hasn't asked him to do because he believes that it is the very kind of thing that God would ask him to do.
And now, what seems like a simple story of disobedience is, in fact, a very complicated story of faith. The same kind of faith that a lot of us have. The same kind of faith that we, thousands of years later, are still wrestling with.