ROME (AP) — Pope Leo XIV opened the church’s penitential Lenten season by presiding over Ash Wednesday and lamenting the “ashes of international law and justice” that have been left by today’s wars and conflicts.

Leo revived the traditional prayer and procession that Pope Francis largely delegated to others in his final years. He walked with dozens of monks, priests, bishops and cardinals from one Roman church to another and then sprinkled ashes on the heads of cardinals during Mass.

Ash Wednesday, a day of fasting and reflection, starts a season of self-denial and repentance from sin known as Lent. The 40-day period leads up to observances of Jesus’ death on Good Friday and resurrection on Easter.

In his homily, Leo offered a meditation on sin and said the ashes that Christians receive bear the "weight of a world that is ablaze, of entire cities destroyed by war.”

“This is also reflected in the ashes of international law and justice among peoples, the ashes of entire ecosystems and harmony among peoples, the ashes of critical thinking and ancient local wisdom, the ashes of that sense of the sacred that dwells in every creature,” he said.

Leo has spoken out strongly against the collapse of the post-World War II international legal order fueled by Russia’s war in Ukraine and even the U.S. military incursion into Venezuela to remove its leader.

Just this week, the Holy See confirmed it would not participate in the Trump Administration’s Board of Peace for Gaza. The secretary of state, Cardinal Pietro Parolin, said the United Nations was the appropriate institution to monitor the currently shaky ceasefire agreement and rebuilding of Gaza.