It's helpful to remember here that the Reformers held to the apostolic admonition to test all things and hold onto what is good, i.e. edifying. It has always been the position of the Confessions that we retain everything that is edifying if the scriptures do not contradict it, and never that we only do what is clearly affirmed in the scriptures. So while it is difficult to argue solely from the scriptures that Christians should confess to their pastor and the pastor pronounce absolution, it is clear that this was the practice from the beginning and as it fits with the scriptures and does not contradict them, the church should retain the practice.