Matthew 5:7

Blessed (content, sheltered by God’s promises) are the merciful, for they will receive mercy.  

Mercy is a two-way street with God because God first extended mercy to us.  We are to be an example of the mercy of God on this earth and walk as Jesus walked.  We cannot hold a grudge against someone and expect God to understand.  God sent Jesus, who died for all, to show love and mercy to us, and we are to walk in this example.