He gave St. Faustina an intention to pray for on each day of the Novena, saving for the last day the most difficult intention of all, the lukewarm and indifferent of whom He said:
"These souls cause Me more suffering than any others; it was from such souls that My soul felt the most revulsion in the Garden of Olives. It was on their account that I said: 'My Father, if it is possible, let this cup pass Me by.' The last hope of salvation for them is to flee to My Mercy."
The different souls prayed for on each day of the novena are:
DAY 1 (Good Friday) - All mankind, especially sinners
DAY 2 (Holy Saturday) - The souls of priests and religious
DAY 3 (Easter Sunday) - All devout and faithful souls
DAY 4 (Easter Monday) - Those who do not believe in Jesus and those who do not yet know Him
DAY 5 (Easter Tuesday) - The souls of separated brethren
DAY 6 (Easter Wednesday) - The meek and humble souls and the souls of children
DAY 7 (Easter Thursday) - The souls who especially venerate and glorify Jesus' mercy
DAY 8 (Easter Friday) - The souls who are detained in purgatory;
DAY 9 (Easter Saturday) - The souls who have become lukewarm.