I will have to settle on Charity as the greatest virtue. Charity also referred as "love" is held to be the highest perfection of the human spirit, because it is said to both glorify and reflect the nature of God. Confusion can arise from the multiple meanings of the English word "love". The love that is caritas is distinguished by its origin, being divinely infused into the soul, and by its residing in the will rather than emotions, regardless of what emotions that manifest. According to Aquinas, charity is an absolute requirement for happiness, which he holds as man's last goal. Keep in mind, Charity has two parts: love of God and love of man, which includes both love of one's neighbor and one's self.