The quote comes from a 19th century French Dominican priest named Jean-Baptiste Henri Lacordaire. He had this to say about what it meant to be a priest:
“To live in the midst of the world without wishing its pleasures; to be a member of each family, yet belonging to none; to share all suffering; to penetrate all secrets; to heal all wounds; to go from men to God and offer Him their prayers; to return from God to men to bring pardon and hope; to have a heart of fire for charity, and a heart of bronze for chastity; to teach and to pardon, console and bless always. My God, what a life! And it is yours, O priest of Jesus Christ!”