("Thanks be to God "). An old liturgical formula of the Latin Church to give thanks to God for graces received. It is found in Scripture, 1 Corinthians 15:57 and 2 Corinthians 2:14.
Deo Gratias occurs in the Mass
The formula Deo Gratias was used in extra-liturgical prayers and customs by the Christians of all ages. The rule of St. Benedict prescribes that the doorkeeper shall say Deo Gratias, as often as a stranger knocks at the door or a beggar asks for assistance. When St. Augustine announced to the people the election of his coadjutor and successor Evodius, they called out Deo Gratias thirty-six times (St. Augustine, Ep. ccxiii al. cx, De Actis Eraclii). In Africa it was the salutation used by the Catholics to distinguish themselves from the Donatists who said: Deo laudes (St. Augustine, In Ps. cxxxi). Therefore in Africa Deo Gratias occurs as a Catholic name, e.g. St. Deogratias, Bishop of Carthage (453-456). The name of the deacon for whom St. Augustine wrote his treatise "De catechizandis rudibus", was Deogratias. St. Felix of Cantalizio (1515-87) used this interjection so often, that the people called him Brother Deogratias.