Mercy is defined as amability, affability, benedicence; mercy is a spiritual gift, a perfection. The beatitude of Jesus: Blessed are the merciful, for they shall be shown mercy, from the Gospel of Mark 5: 7 makes emphasis on the idea of minimizing the suffering, an example of this beatitude is the Parable of the Good Samaritan, in Luke 10:25, the Good Samaritan helps to minimize the suffering of his neighbor.
The concept of minimization of suffering is central to ethics. This idea is inside in any process of improvement from when we seek to improve ourselves until when we seek to improve our society and environment. Underlying this idea is the desire for the good.
Happiness related to this concept is its a return, or to say when we reduce the suffering we are happy. The concept of minimization of suffering is superior to the concept of non-violence. Nonviolence legislates in the sense that tells us what not to do, the problem is that the concept does not prevent violence, only declare and condemns it.
The concept of minimization of suffering goes beyond, because we actively indicates what we must to do to avoid violence. If we avoid suffering we also avoid violence and particularly the violence against ourselves. That silent violence that occurs in the daily battles of life.
The purpose of justice is to maintain friendship among men, but the goal of the mercy goes beyond justice and the desire to maintain equality among men, mercy seeks to alleviate the suffering and violence when justice does not take into account the dignity of men.
The Spiritual gifts are gifts of God and in this case the importance of mercy; is that God's gifts seeks to mitigate the imperfections of virtues, virtues are not all good or complete and therefore sufficient for true friendship and human happiness. When we are mercy with ourselves and with the neighbor we are happy because we attenuate the suffering.
And more, when we act according to the law of God, the Golden Rule, do for others what you would like them to do for you, we heal all violence, the violence against the neighbor, the creation and ourselves.