St Augustine said that the days of the Easter Octave are days of mercy and pardon. St John Paul established this Sunday, the Octave Day of Easter, as “Divine Mercy Sunday.” The gospel recounts Our Lord’s granting to the disciples the power to remit sins, and He shows mercy to St Thomas who had refused to believe.
When Our Lady proclaimed the greatness of the Lord, she said “His mercy is from generation to generation on those who fear Him.” (Lk 1.50) In our practice of devotion to the Divine Mercy in Christ, we fear the Lord because of our sins, but we also trust absolutely in Him because of His promises, His mercy and His power. The prayer placed underneath the Divine Mercy image is “Jesus I trust in you.” St Faustina records how Our Lord promised that He would never reject a soul that trusted in Him.
In the decree establishing the indulgence for today, we are told: “Divine Mercy knows how to pardon even the most serious sins, and in doing so it moves the faithful to perceive a supernatural, not merely psychological, sorrow for their sins so that, ever with the help of divine grace, they may make a firm resolution not to sin any more.”