What the Bible promises is not only that God shows mercy to people, but that people can -- must -- show mercy to each other. Grudges and getting even are a normal part of the world scene, but they have no place in the life of someone who has enjoyed the mercy of God. The Bible promises blessing for people who can mirror God's mercy. It promises something else for those who refuse.
“I pray my child will always know your mercy and become a person who shows mercy to others. May my children always "be merciful, as [their] Father is merciful. (Luke 6:36) …In Jesus name, Amen.”