The process of paper shredding can be quite fascinating. After a document is run through, there is no way to reconstruct it, no way to put it together again, and no way to know what was originally there. We use it to destroy sensitive documents, addresses, and any material we do not want seen.
The shredder is also used for something else - to destroy mistakes. If the wrong form is printed, a name misspelt, or wrong name used -- a quick trip to the shredder and it is as if it never happened. It is gone forever.
But the shredder serves as a reminder of what God has done for us. We envision lists of our mistakes and sins kept somewhere and Jesus taking those lists and running them through the shredder. The evidence of our guilt is destroyed. The list of our sins can never be reconstructed. They are gone forever.
That is exactly what God did when He sent His Son Jesus to die for our sins. Jesus has permanently shredded the list of my sins.