Third Part (Tertia Pars)

Forasmuch as our Saviour the Lord Jesus Christ, in order to "save His people from their sins" (Matthew 1:21), as the angel announced, showed unto us in His own Person the way of truth, whereby we may attain to the bliss of eternal life by rising again, it is necessary, in order to complete the work of theology, that after considering the last end of human life, and the virtues and vices, there should follow the consideration of the Saviour of all, and of the benefits bestowed by Him on the human race.

Concerning this we must consider (1) the Saviour Himself; (2) the sacraments by which we attain to our salvation; (3) the end of immortal life to which we attain by the resurrection.

Concerning the first, a double consideration occurs: the first, about the mystery of the Incarnation itself, whereby God was made man for our salvation; the second, about such things as were done and suffered by our Saviour — i.e. God incarnate.

The Incarnation

GENERAL: The fitness (1) of the Incarnation. The union itself (2).
PERSON: The Person (3) assuming the nature.
NATURE (ASSUMED): The human nature (4): its parts (5) and order (6) of the assumption.
NATURE (CO-ASSUMED): Christ's perfections in grace as an individual man (7) and as Head of the Church (8); of the grace of union (see 2) we have already spoken. Christ's knowledge in general (9) and in particular His divine (see I:14), beatific (10), infused (11) and acquired (12) knowledge. The power (13) of Christ's soul. His defects in body (14) and soul (15).
CONSEQUENCES (CONCERNING CHRIST): The communication of idioms (16) which belong to Christ in being and becoming. The unity of His knowledge (see 9), nativity (see 35), being (17), will (18), and operation (19).
CONSEQUENCES (IN RELATION TO HIS FATHER): Some things—subjection (20), prayer (21), and priesthood (22)—are predicated of Him because of His relation to the Father. Other things—His adoption (23) and predestination (24)—may be predicated of Him because of the Father's relation to Him.
CONSEQUENCES (IN RELATION TO US): Our adoration (25) of Christ. How He is our Mediator (26).

The Life of Christ

CONCEPTION: The sanctification (27), virginity (28), espousals (29), and Annunciation (30) of the mother who conceived Him. The matter (31), author (32) and manner (33) of His conception. The perfection (34) of the child conceived.
BIRTH: His birth (35) and manifestation (36). His circumcision (37) and observance (37) of other legal observances.
BAPTISM: The baptism of John in general(38). The baptizing of Christ (39).
PUBLIC LIFE: His manner of life (40). His temptation (41). His doctrine (42). His miracles in general (43) and specifically (44), with a focus on His transfiguration (45).
PASSION: The Passion itself (46). Its efficient cause (47) and how (48) it was brought about. Its effects (49).
DEATH: His death (50), burial (51) and descent into Hell (52).
RESURRECTION: Christ's Resurrection in itself (53). The quality (54) of the Person rising. The manifestation (55) of the Resurrection and its causality (56).
ASCENSION: His Ascension (57) and His sitting at the right hand (58) of the Father. His judiciary power (59).

The Sacraments

GENERAL: Definition (60) of a sacrament. The necessity (61) of the sacraments and their effects: principally grace (62), and secondarily a character (63). Their causes (64), both as to authorship and as to ministration. Their number (65).

Baptism

BAPTISM ITSELF: The sacrament itself (66). The minister (67), recipients (68) and effect (69) of this sacrament.
PREPARATION: Circumcision (70), which preceded Baptism. Catechism and Exorcism (71), which accompany Baptism.

Confirmation

GENERAL: The sacrament of Confirmation (72).

The Holy Eucharist

GENERAL: The sacrament itself (73). The matter of this sacrament: its species (74), the transubstantiation (75), the real presence (76) and the accidents (77) of bread and wine. The form (78) and effects (79) of this sacrament. The recipient in general (80) and at its institution (81). The minister (82) and the rite (83) of this sacrament.

Penance

PENANCE ITSELF: Penance as a sacrament (84) and as a virtue (85).
EFFECTS: Pardon of mortal (86) and venial (87) sins. The return (88) of sins already forgiven. The recovery of virtues (89).
PARTS (GENERAL): The parts of Penance in general (90).

Editor's Note: St. Thomas never completed his treatise on Penance. The remainder of the Summa Theologiae, known as the Supplement, was compiled probably by his companion and friend Fra Rainaldo da Piperno, and was gathered from St. Thomas's commentary on the Fourth Book of the Sentences of Peter Lombard.