8 But again: Whom did Philip preach to the eunuch of the queen of the Ethiopians, returning from Jerusalem, and reading Esaias the prophet, when he and this man were alone together? Was it not He of whom the prophet spoke: “He was led as a sheep to the slaughter, and as a lamb dumb before the shearer, so He opened not the mouth?” “But who shall declare His nativity? For His life shall be taken away from the earth.” [Philip declared] that this was Jesus, and that the Scripture was fulfilled in Him; as did also the believing eunuch himself: and, immediately requesting to be baptized, he said, “I believe Jesus Christ to be the Son of God.” This man was also sent into the regions of Ethiopia, to preach what he had himself believed, that there was one God preached by the prophets, but that the Son of this [God] had already made [His] appearance in human nature (secundum hominem), and had been led as a sheep to the slaughter; and all the other statements which the prophets made regarding Him.
Source: Adversus haereses (New Advent)