Catholic Teachings
Solidarity is the notion that we're connected with our neighbors: down the street, throughout the country, and around the world. We can't, as Christians, just say “I'll take care of myself, I don't care about my poor next-door neighbor.” Likewise, we can't, as Christians, just say, “I'll take care of America, I don't care about the poor Third World.”. The principle of solidarity means we are all really responsible for each other. To Cain’s question “Am I my brother’s keeper?” (Gen 4:9) God answers, yes! Pope Benedict defines it as “a firm and persevering determination to commit oneself to the common good; that is to say to the good of all and of each individual, because we are all really responsible for all.”