Charity is literally one of the seven virtues which are thought of as opposites to the seven vices or sins (or to take a page from Buddhism, "antidotes" to the "poisons" of the vices).

It's not exactly " charity" as we know it. The Latin word is "caritas" which means "caringness" basically but the Greek word is "agape" which is a saintly kind of love. Compare the increasing intensity of love involved in sympathy/empathy/compassion or love for a friend/family/partner/all beings.

Compassion is literally the thing of saints and which allows one to sit calmly while being tortured to death as a martyr. One of the most haunting things I have seen is that image of Thích Quảng Đức so calmly protesting the South Vietnam government's persecution of Buddhists (CW: suicide by self-immolation). I imagine that is how the Christian martyrs must have held themselves in their last moments