Milk of human kindness

Care and compassion for others is pure Shakespeare from Macbeth, Act I, Scene V, spoken by Lady Macbeth musing on her husband’s character, “Yet I do fear thy nature; it is too full o’ the milk of human kindness.” Sheridan plagiarised it in The Rivals (1775) Act III, Scene IV when he wrote, “The thunder of your words has soured the milk of human kindness in my heart.”