While the feast of Divine Mercy was instituted by St John Paul II based on the private revelation of St Faustina, divine mercy itself is scriptural. A search for the word mercy or mercies in the Douay Rheims Bible shows these two words were used 503 times in 468 verses. The Book of Psalms uses these two words 160 times. Since the Book of Psalms is a book of prayer, this shows God wants to remind us of his mercy.
The word mercy however is an often abused word. Many people today have the idea that since God is merciful, I can do whatever I want without any consequence. This is not mercy. This is irresponsibility. The Psalm today tells us: the Lord has punished me severely, but he did not give me over to death. Mercy does not mean I can do whatever I want. It means Jesus has taken on himself the punishment due to us so we can be forgiven. There are consequences to rebellion against God, but the mercy of God moves him to look at what Jesus did and use the merits of the sacrifice of Jesus to take away our sins.
This is why the Gospel tells us John wrote his work so you may come to believe that Jesus is the Christ (Messiah), the Son of God and that through believing you may have life in his name. God’s mercy calls us to an intimate relationship with him through the Messiah he has chosen so that when we trust and surrender our lives to him, we will have eternal life. Eternal life is available when we come to him. While it is a free gift, we need to come to God, reach out and get it. God will not give it to us if we do not ask. But when we ask, St Paul tells us in the Second Reading we will conquer the world because we will believe Jesus is the Son of God. We become children of God when we love God and obey his commandments.
The love of God is seen in the unity of the Church as seen in the First Reading where we are told those who believed were of one heart and soul. This unity in heart and soul is in the teaching based on what Jesus taught as handed through centuries. There are many today who maliciously teach the wrong gospel and expect no resistance to the false gospel they teach, accusing those who resist as causing disunity. These false teachers are not acting in mercy and love because by teaching a false gospel, they are not giving life to those who hear. They are teaching falsehood and leading people to hell with them because of their false idea of mercy and love. The disunity is caused, not by those who hold to the true teaching of Christ, but by those who teach a false gospel.
God is merciful. God is love. But God is not mocked by those who preach a false gospel. Mercy comes from love and if an action does not result in life, that is not an act of mercy. That is an act of murder because the person who teaches it leads another to death.
Lord, help me to hold to the truth. In your mercy, reveal false prophets so they will not lead others to condemnation.