Vatican City, Feb 13, 2017 / 10:40 am (CNA/EWTN News).- Pope Francis on Monday spoke about what it means to kill your brother in your heart, which, may be something as small as envy or bitterness, and if left to grow, can lead to even worse things, such as war or actual murder. Most people have never actually killed someone, the Pope said in his homily for Mass at the chapel of Casa Santa Marta Feb. 13, but “if you have a bad feeling toward your brother, you killed him; if you insult your brother, you killed him in your heart. Killing is a process that starts from little things.”

Reflecting on the story of Cain and Abel, the Pope said it is one “which begins with a little jealousy: Cain is irritated because his sacrifice does not please the Lord and he begins to cultivate a feeling of resentment, a feeling he could control but does not.” “The speck of sawdust becomes a plank in our eye,” he continued, “our life revolves around it and it ends up destroying the bond of brotherhood; it destroys fraternity.”

When we let even these little things, like resentment or jealousy or annoyance, continue, Francis said, the sin can grow into something even worse. “This is what happened to Cain, who ended up killing his brother.” This is why we must try to stop, at the very first sign of bitterness and resentment, he said. “Bitterness is not Christian. Pain is, but not bitterness. Resentment is not Christian.” If we do not do this, “this enmity ends up destroying families, people, everything!” he said.

Giving an example from war, where people may say that casualties of bombs or other violence, even children, are not their fault. “It all begins with that feeling that makes you break away, saying to each other: ‘This is some guy, this is so and so, but it is not a brother…’” he said, or when we say “here are those who are bombarded” or “who are driven out” but “these are not brothers.”  

The Pope gave his homily to the members of the Council of Cardinals. The council, an advisory board to the Pope made up of nine cardinals, started their 18th session today, which runs through Feb. 15. Pope Francis created the group at the start of his pontificate to act as an advisory body on Church governance and reform of the Roman Curia.

The Pope offered the Mass for Father Adolfo Nicolás, the Superior General of the Jesuits from 2008 to 2016, who will be leaving Rome Wednesday.

This lack of brotherhood infects even the priesthood, the Pope warned: “little things… rifts.” Cain’s answer “is ironic,” because when the Lord asks him where his brother is, he says, “I don’t know: am I my brother’s keeper?” Francis said. “Yes, you are your brother’s keeper,” the Pope emphasized.

Let us ask the Lord, the Pope concluded, to remember this question: “Where is your brother?” and to help us think about “all those who in the world are treated as things and not as brothers, because a piece of land is more important than the bond of brotherhood.”