‘Non-slanderous evaluation is fair-minded, constructive, gentle, guarded, and always demonstrates that speakers sense how much they share the same frailty, humanity, and sinful nature with the one being criticized. It shows a profound awareness of your own sin. It is never “against-speaking.”

It’s from: Should You Pass on Bad Reports? -Tim Keller & David Powlison

http://www.monergism.com/thethreshold/articles/onsite/passon.html