This attack followed one day after a bomb exploded between two metro stops in St. Petersburg, killing 14 people and injuring dozens more. Authorities have determined the attack was carried out by a suicide bomber originally from the central Asian Republic of Kyrgyzstan, CNN reports.

Another explosive device was later found in the metro system and safely disabled.

Pope Francis said Wednesday that his thoughts go out to all those involved in the serious attack. “I entrust to God's mercy those who have tragically died, I express my spiritual closeness to their families and to all those who suffer because of this tragic event,” he said.

The Pope’s appeal followed his usual Wednesday general audience in St. Peter’s Square, where he spoke about what it means to accept suffering in our lives, uniting it with the suffering of Jesus on the Cross.

St. Peter tells us it is better to suffer “for doing good...than for doing evil,” Francis said. “He does not mean that it is good to suffer, but that, when we suffer for the good, we are in communion with the Lord, who consented to suffer and be placed on the cross for our salvation.”

“When then we too, in smaller or larger situations in our lives, accept to suffer for the good,” he continued, “it is as if we sow around us seeds of the resurrection, seeds of life, making shine in the darkness the light of Easter.”

This is why the Apostle urges us to not return “evil with evil,” he said, but instead to always wish the other person well.

“This blessing is not a formality, is not only a sign of courtesy, but is a great gift that we ourselves have receive and have to ability to share with others,” he said. “It is the proclamation of God, an immense love, that does not end, it never fails, and which constitutes the very foundation of our hope.”

Every time we suffer “for righteousness,” we become an “instrument of peace,” the Pope said. This is why the Apostle Peter calls us “blessed” for doing so.

St. Peter also tells us to “always be ready to give an explanation to anyone who asks you for a reason for your hope,” but this hope is not just a concept or a feeling, but a person, Pope Francis said.

Because “Christ is risen,” we recognize that he is not only alive, but present in us and in our brothers and sisters, as well, he said. This means that we must be Christ’s visible signs on earth, taking him as our model of how to live and learning to always act as he would act.

We must “emanate” the gentleness of Christ, always showing respect towards others, forgiving those who hurt us, the Pope said.

“Yes, because that is what Jesus did, and continues to do through those who make room for him in their hearts and in their lives, aware that evil does not win with evil, but with humility, mercy and meekness."