"For the sake of His sorrowful Passion, have Mercy on us and on the whole world."
I pray this prayer every day, when I say the chaplet of Divine Mercy. According to Saint Faustina, Jesus urged the practice of praying this repeatedly, using the beads of the Rosary, promising that this "chaplet" would be a source of great and special graces for us and for the world (if you don't know this prayer already, see this LINK).
When I pray the chaplet, I seek to unite myself spiritually to the offering of the Holy Sacrifice of the Mass, because it is through the Eucharist that I can pray the prayer at the beginning of each decade: "Eternal Father, I offer you the Body, Blood, Soul, and Divinity of Your dearly beloved Son Our Lord Jesus Christ, in atonement for our sins and those of the whole world."
These prayers express so much about the love of the Father, the truth about our sins, and our total dependence on the mystery of Christ's sacrifice. But sometimes I have wondered: where is the Holy Spirit in this prayer? Then I thought (and this is just my own opinion), that Mercy itself refers to the Holy Spirit. Through the redeeming sacrifice of the Son of God made man, the Father and the Son breathe forth the Spirit upon the world, and into the hearts of those who receive God's saving love.
The Divine Mercy devotion and the special icon given to Saint Faustina focus on the "blood and water" that flowed forth from the Heart of Jesus. But as Saint John tells us, "there are three that bear witness...the Spirit, and the water, and the blood; and these three are one" (1 John 5:7-8). In some sense, can we not think of the Mercy of God as the gift of His Spirit?
Then, the prayer of the chaplet becomes a Trinitarian prayer: "For the sake of His [the Son's] sorrowful Passion, [Father] have Mercy [send Your Holy Spirit] on us and on the whole world." I don't see any reason why it cannot be understood in this way, but the more important thing is that I know that when I pray the chaplet and implore God's Mercy for me and for the world, I am begging for the grace of the Holy Spirit, by which God works the miracle of His Mercy in me, and embraces in His Mercy all those who have been entrusted to me - those who need my prayers. I want to lift up my heart and immerse myself in the mystery of the Holy Trinity, of the God who is Love, and who is my only hope.
And I beg for that Love to be poured out as healing mercy on a poor world that is so broken and so full of longing and suffering and deception and violence — a world that I feel inside my own heart, crying out for a love it does not know, crying out for the Presence of Christ to radiate love within it through me.