As the Catechism of the Catholic Church explains, "To receive in truth the Body and Blood of Christ given up for us, we must recognize Christ in the poorest, his brethren" (no. 1397).
"Catholic social teaching is a central and essential element of our faith."
Catholic social teaching emerges from the truth of what God has revealed to us about himself. We believe in the triune God whose very nature is communal and social. God the Father sends his only Son Jesus Christ and shares the Holy Spirit as his gift of love. God reveals himself to us as one who is not alone, but rather as one who is relational, one who is Trinity. Therefore, we who are made in God's image share this communal, social nature. We are called to reach out and to build relationships of love and justice.
Catholic social teaching is based on and inseparable from our understanding of human life and human dignity. Every human being is created in the image of God and redeemed by Jesus Christ and therefore is invaluable and worthy of respect as a member of the human family. Every person, from the moment of conception to natural death, has inherent dignity and a right to life consistent with that dignity. Human dignity comes from God, not from any human quality or accomplishment.
Our commitment to the Catholic social mission must be rooted in and strengthened by our spiritual lives. In our relationship with God, we experience the conversion of heart that is necessary to truly love one another as God has loved us.
---from Sharing Catholic Social Teaching: Challenges and Directions