There are seven main forms of this devotion:

1. The Divine Mercy image with the specific inscription Jesus, I trust in You;
   
2. The commemoration of the Feast of the Divine Mercy Sunday;
   
3. The recitation of the Chaplet of the Divine Mercy;
   
4. The recitation of the Divine Mercy Novena;
5. The designation of the Hour of Mercy at 3:00 am or 3:00 pm.;
   
6. Spreading mercy by word, deed, or prayer; and
7. Proclaim that mercy is the greatest attribute of God. The spreading of works of mercy to the whole humanity, in preparation for the return of Jesus Christ to Earth.

As in the prayers that form the Chaplet of Divine Mercy, there are three main themes to the Divine Mercy devotion: to ask for and obtain the mercy of God, to trust in Christ's abundant mercy, and finally to show mercy to others and act as a conduit for God's mercy towards them.

The first and second elements relate to the signature "Jesus I trust in You" on the Divine Mercy image and Kowalska stated that on April 28, 1935, the day the first Divine Mercy Sunday was celebrated, Jesus told her: "Every soul believing and trusting in My Mercy will obtain it."

The third component is reflected in the statement "Call upon My mercy on behalf of sinners" attributed to Jesus in Kowalska's diary (Notebook I, items 186–187). This statement is followed in the diary by a specific short prayer: "O Blood and Water, which gushed forth from the Heart of Jesus as a fount of Mercy for us, I trust in You." which Kowalska also recommended for the Hour of Divine Mercy In her diary (Notebook II, item 742) Kowalska wrote that Jesus told her: "I demand from you deeds of mercy, which are to arise out of love for Me." and that he explained that there are three ways of exercising mercy toward your neighbor: the first-by deed, the second-by word, the third-by prayer.

The Divine Mercy devotion views mercy as the key element in the plan of God for salvation and emphasizes the belief that it was through mercy that God gave his only son for the redemption of mankind, after the fall of Adam.[19] The opening prayer for Divine Mercy Sunday Mass refers to this and begins: "Heavenly Father and God of Mercy, We no longer look for Jesus among the dead, for He is alive and has become the Lord of Life". ✠