In Matt 5:7, Jesus teaches that when we give mercy, we shall be given mercy.  It is the law of sowing and reaping.  When you give something it is returned to you by God and others.  Walking in mercy means that you have the power to punish or hurt someone and you choose not too.  In the movie Schindlers list there is a story where Schindler tries to teach the evil Nazi commander about mercy.  At first he succeeds and then reverts back to his former self but the reality is that mercy is a choice.  You choose to be merciful.  Jesus said that when you are merciful, God will be merciful.  Today choose to walk in mercy and grace.  Choose to be the hand of God and show His love, acceptance and forgiveness to all those you come into contact with.  All these qualities are a choice.  So today choose to be walk in mercy because that is what will come back to you.