Catena Fidei

Acts 9:20 (WEB)
Immediately in the synagogues he proclaimed the Christ, that he is the Son of God.

Catechism · 1

§442Article 2 · "And in Jesus Christ, His Only Son, Our Lord"Read at vatican.va
“…Son to me, in order that I might preach him among the Gentiles..." "and in the synagogues immediately [Paul] proclaimed Jesus, saying, 'He is the Son of God.'"” — Catechism footnote: Acts 9:20.

Irenaeus of Lyons, Against Heresies III.12Book III
“…his sight, and be baptized—“preached,” it is said, “Jesus in the synagogues at Damascus, with all freedom of speech, that this is the Son of God, the Christ.”” — editor's note: Acts ix. 20.
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Augustine of Hippo, Expositions on the Psalms Psalm 59
“Saul out of a wolf was made a dog at evening, that is, being late converted by the crumbs of his Lord, in His grace he ran, and went around the city.” — editor's note: Acts ix. 1, 20.
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Augustine of Hippo, Harmony of the Gospels I.10Book I
“…was grievously persecuting those who had become believers in Christ, did Christ call that man [by a voice] from heaven, and made him His disciple and apostle.” — editor's note: Acts ix. 1–30.
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John Chrysostom, Homilies on Matthew Homily 68
“For they indeed supposed that He was a mere man, wherefore also they said, “the Son of David;”but He to correct this brings in the prophet witnessing to His being Lord, and the genuineness of His Sonship, and His equality in honor with His Father.” — editor's note: It may be in this view that it is said of St. Paul, immediately on his conversion, that “he preached Christ in the synagogues, that He is the Son of God.” Acts…
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Tertullian, On Baptism Chapter 12
“That point excepted, he had sufficiently learnt and believed “the Nazarene” to be “the Lord, the Son of God.”” — editor's note: See Acts ix. 1–31.
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Ambrose of Milan, On the Holy Spirit II.13Book II
“He believed who used to make havoc of the Churches; but being converted to the faith, he preached in the Spirit that which the Spirit commanded.” — editor's note: Acts ix. 20.
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