Compassion is a human virtue

It has sometimes been claimed that faith, hope and charity (and possibly also forgiveness) are specifically Christian virtues. For example, G K Chesterton claimed this. They are certainly held in high esteem by Christians, but that does not mean that Christians invented them.

But ancient pagans certainly included compassion among their values.

The Religio Romana website lists a number of Roman virtues, including:

• Aequitas: Equity; fairness and justice within society and government
• Caritas: Affection; To love, cherish and hold dear, especially within family
• Clementia: Clemency; Mildness, gentleness, mercy, compassion in private and public matters
• Concordia: Concord; Harmony, agreement between peoples and nations
• Fides: Good Faith; Trust, fidelity, fulfilment of promises made
  
• Humanitas: Humanity; Kindness, being refined, cultured and educated, embracing the best aspects of civilization
• Indulgentia: Indulgence; Permissiveness, leniency, tolerance
• Justitia: Justice; Equitable, fair treatment, guided by principles, also defined by implementation and enforcement of reasonable laws within a sound government
• Liberalitas: Liberality; Generosity; to give abundantly
• Munificentia: Munificence; Benevolent, bountiful service, charitable
• Spes: Hope; A belief in favorable outcome particularly in times of struggle

(note that the above list includes faith, hope and charity!)

Ancient heathens also extolled the virtues of generosity to others less fortunate than oneself; the Hávamál contains many stanzas about hospitality (still widely considered a virtue in Germanic culture).

Compassion is also extolled in the Wiccan core text, The Charge of the Goddess; and hospitality is one of the Nine Noble Virtues of modern Heathenry.

And of course there are many compassionate atheists, who give money to secular charities. Compassion is a human virtue; it doesn't belong to any specific religion.