Charity is a supernatural virtue infused with sanctifying grace, by which we love God above all as the greatest good and for His own sake, and ourselves and our neighbors for the love of God.
It is the greatest of the three theological virtues (faith, hope and charity) and of all virtues. The object of the virtue is our union with God through love; the act itself is the giving of ourselves to God.
Charity is given as the greatest commandment in Matthew 22:34–40, and it is joined inseparably by the command to love one’s neighbor.
Although charity may be manifested in many ways, it is not to be confused with almsgiving as such, nor is it only good deeds that may arise out of natural virtue and the emotion of goodwill or compassion.
Rather, charity is the very basis, the foundation that prompts, and is the motivating force by which all acts of good directed toward ourselves or our neighbors are performed for love of God. (7:48)