Archbishop Gabriele Caccia, the Vatican’s Permanent Observer to the United Nations, celebrated Mass on Sunday as part of Sant’ Egidio’s four-day Vigil for Peace in Manhattan to mark the anniversary of the atomic bombings of Hiroshima and Nagasaki in August 1945.

In his homily, Archbishop Caccia talked about the “light” and “cloud” mentioned in the day’s Gospel reading for the Feast of the Transfiguration and how different the meaning of those words is in the context of the atomic bombs dropped on Hiroshima and Nagasaki in August 1945.

In attempting to discern the real light of God, he said, “we can be deceived,”noting that there are those who think the atomic bomb was good because they say it helped to end the war. “Sometimes,” he said, “we are deceived by our own reasons. We transform what is bad into what seems to be not that bad, even good.”

“Mankind must put an end to war, or war will put an end to mankind,” Archbishop Caccia said, quoting President John F. Kennedy, adding that this is especially true when we think of nuclear weapons.

He noted that in Ukraine “they are talking, again, about tactical nuclear weapons,” lamenting, “we don’t learn, we don’t discern.”

Watch Archbishop Caccia’s full homily in the video above.

Note: audio quality is variable.