Blessed are the merciful: for they shall obtain mercy.
If we desire mercy to be shown to us, then we must be willing to show mercy to others. There are many times in the Bible that this principle is shown. Christ tells the parable of the king who took account of his servants. When he saw one servant owed him lots, he was prepared to throw him in jail until the servant begged mercy. The king showed mercy, but then the servant wet out and denied mercy to someone else who owed him money. When the king found out, he had the first servant thrown in jail because of his lack of mercy to others (Matthew 18:23-34).
Christ even tells us this principle is the law in Matthew 7:12 and even the world considers it a good principle-"Do unto others as you would have them do unto you."
Show mercy if you desire mercy shown to you!