a) Christ Himself solemnly commanded His Apostles and their successors to preach the Gospel to all nations, and before baptizing them to convert them to a firm belief in certain specified truths which no man may reject except at the peril of his eternal salvation.
α) Mark XVI, 15 sq.: “Go ye into the whole world, and preach the gospel(784) to every creature: He that believeth [_i.e._ in the Gospel] and is baptized, shall be saved; but he that believeth not shall be condemned.” Agreeable to this injunction St. John declares it to be the object of his Gospel “that you may believe that(785) Jesus is the Christ, the Son of God, and that believing, you may have life in his name.”(786) The Gospel is written “that we may believe.” What must we believe? That “Jesus is the Christ, the Son of God.” This is a revealed truth by firmly believing which we shall be saved. When the treasurer of Queen Candace begged to be baptized, Philip the deacon said to him: “If thou believest with all thy heart, thou mayest.” The eunuch replied: “I believe that Jesus Christ is the Son of God,” whereupon Philip baptized him.(787)
β) St. Paul in his Epistles to the Romans and the Galatians eloquently insists on the necessity of faith, not a mere _fides fiducialis_, but a believing acceptance of Divine Revelation. Cfr. Rom. X, 9 sq.: “For if thou confess with thy mouth the Lord Jesus, and believe in thy heart that God hath raised him up from the dead, thou shalt be saved. For with the heart we believe unto justice, but with the mouth confession is made unto salvation.”(788) We must confess with the mouth and believe with the heart. External profession and internal faith go together and have for their common object a certain truth open to our knowledge, _viz._: the resurrection of Christ,—a dogma in which the whole teaching of the atonement lies imbedded.
The character of justifying faith is still more plainly evident from Heb. XI, 6: “Without faith it is impossible to please God. For he that cometh to God [he that is to be justified], must believe that He is [the existence of God], and is a rewarder to them that seek Him.”(789) The Apostle here clearly asserts both the necessity of justifying faith and the minimum of doctrine to be explicitly “believed,” _viz._: the existence of God and eternal retribution.(790)