In 1933, God gave Sister Faustina a striking vision of His Mercy, Sister tells us:

“I saw a great light, with God the Father in the midst of it.  Between this light and the earth I saw Jesus nailed to the Cross  and in such a way that God, wanting to look upon the earth, had to
look through Our Lord’s wounds. And I understood that God blessed  the earth for the sake of Jesus.”

Of another vision on Sept. 13, 1935, she writes:

“I saw an Angel, the executor of God’s wrath… about to strike  the earth…I began to beg God earnestly for the world with words  which I heard interiorly. As I prayed in this way, I saw the
Angel’s helplessness, and he could not carry out the just  punishment….”

The following day an inner voice taught her to say this prayer on  ordinary rosary beads:

“First say one ‘Our Father’, ‘Hail Mary’, and ‘I believe’. Then on  the large beads say the following words:

‘Eternal Father, I offer You the Body and Blood, Soul and Divinity  of Your dearly beloved Son, Our Lord Jesus Christ, in atonement  for our sins and those of the whole world.’

On the smaller beads you are to say the following words:

‘For the sake of His sorrowful Passion have mercy on us and on the  whole world.’

In conclusion you are to say these words three times:

‘Holy God, Holy Mighty One, Holy Immortal One, have mercy on us
and on the whole world’.

Jesus said later to Sister Faustina:

“Say unceasingly this chaplet that I have taught you. Anyone who  says it will receive great Mercy at the hour of death. Priests  will recommend it to sinners as the last hope. Even the most
hardened sinner, if he recites this Chaplet even once, will  receive grace from My Infinite Mercy. I want the whole world to  know My Infinite Mercy. I want to give unimaginable graces to
those who trust in My Mercy….”

“….When they say this Chaplet in the presence of the dying, I  will stand between My Father and the dying person not as the just  judge but as the Merciful Savior”.