"Then let us bring again the ark of our God to us; for we did not turn to it in the days of Saul." -I Chronicles 13:3
There is no reason given for David moving the ark to Jerusalem in II Samuel. There's no mention of Saul at all. So why is this necessary here?
The importance of this goes beyond the fact that Saul seems to have ignored the ark. Again, we have to put this in context. I Chronicles is written after the Exile. The returned Hebrews are asking, "What now?" It's easy to miss, but the writer of I Chronicles just provided an answer, "We need to return to God." Like Saul before David, the pre-Exile Hebrews had neglected their relationship with God. Now, the Hebrews that God had established once again in Jerusalem (just like David) must return to God (just like David). The point of the extra detail (that Saul had neglected the ark, but David didn't) isn't in the detail itself; the point is in why the detail is mentioned at all.
Like I said in my last post, these differences will stack up, and as they do we'll see more and more why the books of Chronicles were written. I'll try to point out these differences as we come across them.
Stopping point: I Chronicles 14