'We need not, and cannot, add to what Jesus has done. We do not need, and are not able, to do anything more to have a cleansed consience. Imagine going in to a famous art gallery wth a child's paintbrush and paints in your coat pocket. You stand before some great work of art by Rubens or Michaelangelo, quietly get out your paintbrush and - when the attendants are not watching - start adding your own touches of paint. When challenged, you say, "Well, it's a lovely painting. But I thought it had a few parts missing. So I was touching it up. I hope that's OK." No, it is not OK. You are ruining it! In the same way, I cannot add anything to Jesus' completed work of redemption on the cross, without taking away from its value.'
Christopher Ash, Pure Joy, p.139.
