Zaremba says Vatican Radio mentioned the devotion a number of times. I am guessing this was the Polish service. In fact, on February 24, 1948, there was a special broadcast entitled "Sister Faustina, the Apostle of the Mercy of God." It talked about her life and "mentioned that Jesus was pleased with her humble soul and chose her to lead many souls to His Mercy" (Zaremba, 89). The novena, chaplet, and feast were mentioned, and even some of the promises Jesus gave for those who venerated the image of Divine Mercy.
"This rather unusual broadcast finally concluded with the thought that Christ is warning the world that it stands on the brink of misfortune and destruction, and inviting it to cast itself into the arms of God's mercy, which desires to be the world's true Life and Happiness, Order and lasting Peace" (Zaremba, 90).
Indeed, that thought from 1948 has no less relevance today than it did then. One of the last messages St. Faustina received from Jesus echoes this:
How very much I desire the salvation of souls! My dearest secretary, write that I want to pour out My divine life into human souls and sanctify them, if only they were willing to accept My grace. The greatest sinners would achieve great sanctity, if only they would trust in My mercy. The very inner depths of My being are filled to overflowing with mercy, and it is being poured out upon all I have created. My delight is to act in a human soul and to fill it with My mercy and to justify it. My Kingdom on earth is My life in the human soul. Write, My secretary, that I Myself am the spiritual guide of souls – and I guide them indirectly through the priest, and lead each one to sanctity by a road known to Me alone. (Diary, 1784)