PARIS (CNA) — In a Mass at Notre Dame Cathedral, the archbishop of Paris said despite the uncertainty and grief surrounding the terrorist attacks in the city last week, God is the source of strength and hope.

“It’s an understatement to say that the savage killings of this black Friday have plunged entire families into deep distress,” Cardinal André Vingt-Trois reflected Sunday in his homily. “And this anxiety is all the more profound when there aren’t any rational explanations that would justify the indiscriminate execution of dozens of people they didn’t even know.”

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When the pain and confusion become too great to bear, the cardinal asked, “Who can we turn to in this trial?”

“It’s an understatement to say that the savage killings of this black Friday have plunged entire families into deep distress.”

He proposed that there are ultimately only two options: the “tranquilizers” of this world or “the God of life.”

The Mass at Notre Dame was offered for the victims of last Friday’s attacks in Paris. At least 129 people were killed and more than 300 injured in a series of bombings and shootings throughout the city. ISIS has claimed responsibility for the attacks.

Vingt-Trois reflected on how “the Christian faith can be of some help to us in the confusion that has fallen upon us.”

In addition to the pain and unanswered questions surrounding the attacks themselves, he said, the atrocity of last Friday reminds all the mourning people of France and the whole world of the “inescapable reality” that “whether close or far off … our existence is marked by death. We can try to forget it, get around it, to want to soften and lighten it, but it’s there.”

“We don’t know the day or the hour of our own end, and not knowing this troubles a lot of people,” he said. “But we all see — and what happened … reminds us cruelly, that death’s work never ends and sometimes strikes blindly.”

Vingt-Trois reflected on how “the Christian faith can be of some help to us in the confusion that has fallen upon us.”

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While it may not be possible to fully understand the evil that happens in this life, believers can hold on to hope and bear witness to it as they comfort the suffering, Vingt-Trois said.

Strength in face of these trials, he explained, “comes from our confidence in God and our ability to rely on him.”

“So we can’t allow ourselves to be stopped by the misfortunes of life or the suffering that we’re enduring, as if this had no meaning. Through them, we can discover that God is knocking on our door and wants to call us again to life, and open up to us the ways of life,” he said.

“This confidence in God is a light on the journey of life,” the cardinal said, encouraging those gathered to “put our trust in God, who is the God of life.”

This article originally appeared in Catholic News Agency.