助人为乐/乐于助人：take pleasure in helping people; be ready to help others; be generous in giving help; offer a helping hand
Eg: People want to work with individuals who are responsive and quick to offer a helping hand.
救死扶伤：heal the wounded and rescue the dying
Eg: Their duty is to heal the wounded and rescue the dying.
守望相助：offer mutual support and assistance in times of adversity; keep watch together in mutual defense
Eg: Offering mutual support and assistance in times of adversity is a traditional virtue of the Chinese nation.
见义勇为：do boldly what is righteous; act bravely for a just cause
Eg: Everyone admires his spirit of doing boldly what is righteous.
舍己救人：risk one’s life to save others; save others’ lives at the risk of one’s own
Eg: The heroes made an instant decision to risk their own lives to save others.