Divine Mercy Sunday (a.k.a. the Feast of the Divine Mercy) is celebrated on the second Sunday of Easter and concludes the Octave of Easter. 

Divine Mercy Chaplet is a prayer given to St. Faustina by Jesus as a means for honoring His Sacred Passion that also implores mercy for poor sinners and the world.

“I demand from you deeds of mercy, you must not shrink from this or try to excuse or absolve yourself
from it. I give you three ways of exercising mercy, the first by deed, the second by word, and the third by
prayer. In these three degrees are contained the fullness of mercy, and it is an unquestionable proof of
love for Me. By these means a soul glorifies and pays reverence to My mercy.” (Diary of Saint Faustina
742.)
Learn more about Divine Mercy with a 15-minute video presentation by Fr. Michael Gaitley, MIC
followed by a 15-minute Divine Mercy Chaplet prayer at the following website:
www.thedivinemercy.org/message/divine-mercy-crash-course