We can first look at how we are formed with the natural law written on our hearts. We maintain that echo of the supernatural gifts from the Garden (although wounded by the Original Sin) which remind us constantly in our conscience of what is right and what is wrong, to seek the good to which we are ultimately called. It sparks in us a compassion for others, if properly regarded; we are keenly aware, even without the Gospel that our life and the lives of others are precious. A beautiful example of this in the Old Testament is when Abraham pleads to God for mercy on the city of Sodom (cf. Gen 18: 16-33). It is his mission in conversation with God to show his own level of compassion for the people of the city, and to be their voice before God. In turn, his plea is heard and honored. Another example of manifold mercy is that of Joseph when he was sold into slavery in Egypt. He is shown compassion when he interprets Pharaoh’s dream and is given a position in Egyptian leadership as a result; he then turns to his brothers who are seeking food because of famine in Israel – those same brothers who schemed, sold him into slavery and lied to his father about his death – tests them and then shows them mercy and forgiveness; in the end, Pharaoh shows mercy to the entire family and establishes for them a place of comfort and prestige in Egypt (cf. Gen 37- 45). The instances of mercy in the Old Testament are too numerous to list, but each begins and ends with the person being moved by a desire to do the will of God even if it wasn't immediately apparent that this motivation was the impetus to the act of mercy.
In the coming of Christ Jesus and His teachings throughout His public ministry, it is clear that we are to deepen this natural inclination to show mercy toward others. Jesus brings that echo from the Garden into full resolution. He teaches us Two Great Commandments upon which the Ten Commandments are ultimately based:
You shall love the Lord, your God, with all your heart, with all your soul, and with all your mind. This is the greatest and the first commandment. The second is like it: You shall love your neighbor as yourself. The whole law and the prophets depend on these two commandments (Mt 22:37-40).The whole law, the prophets depend on these. Everything is established in these two commandments. Mercy is based on these commandments. When Jesus commissions the apostles to forgive sins, to make disciples in every nation, there is at the heart of this a need to show mercy and compassion (cf. Jn 20:23; Mt 28:19-20). They would not be well received, they were changing centuries of thought and belief and were contradicting social norms in every culture. This mission of mercy could not happen without the grace that came from the Passion, Death and Resurrection of Jesus.
Pope Francis reminds each of us in his teaching:
For the mercy we receive from the Father is not given solely for our benefit, but for the good of all, by transforming us into instruments, missionaries of mercy. By being such missionaries, we come to experience more deeply the gift of mercy in our own lives.To be a missionary of mercy, then, is to recognize that first we have the law written on our hearts – that natural inclination to do good and avoid evil – then, we receive the grace to share the Gospel message with others, showing them mercy and forgiveness, by virtue of Christ Jesus and his commissioning. Pope Francis entreats each of us to embrace that we are “bearers of Christ”.