"It goes without saying that neither merciful men nor angels need to inform God of what is happening in the world, that God should know in this way, for the most high God is all-knowing and all-seeing. All that they see and understand they do by God's help. Why, then, does it say that the servants saw what was done by their merciless fellow-servant and told their lord? In order to show the compassion of good men and angels. Because it is the will of God Himself that all His faithful servants rejoice in good and grieve at sin. God's sorrowful servants, then came and informed their lord of what was happening. (Mt. 18:31) "
St. Nikolai Velimirovic.