The above verses are loosely taken from the Authorized Version (KJV), (the italics are missing, italicized type was used by the KJV to indicate words added by the translators to help the reader).
When discussing textual differences between versions it's a good idea to add the version you are quoting.
Why is it important to know what version is used?
The AV was translated primarily from Greeks texts commonly known as the
Textus Receptus.
The base Greek text of the T
extus Receptus was derived from a limited number of hand-written manuscripts copied centuries after the original documents.
Acts 8:37 is printed in many modern translations as a footnote. It is footnoted in the text of The Greek New Testament according to the Majority Text, (Hodges and Farstad), the Byzantine Version, and Westcott and Hort’s version of the GNT (the forerunner of the modern Critical Text).
Modern translations incorporate the many thousands of ancient manuscripts including papyrus the have been uncovered, some from as early as the second century.
Theory: As manuscripts were copied, notes of clarification were occasionally added beside or within the text (in a similar fashion as footnotes are added into study Bibles today).
Supporting this theory, Philip Comfort writes:
If the verse was an original part of Luke’s text, there is no good reason for explaining why it would have been omitted in so many ancient manuscripts and versions. Rather, this verse is a classic example of scribal gap-filling, in that it supplied the apparent gap left by the unanswered question of the previous verse (“The eunuch said, ‘Look, here is water! What is to prevent me from being baptized?’ ”). The interpolation puts an answer on Philip’s lips that is derived from ancient Christian baptismal practices. Before being baptized, the new believer had to make a confession of his or her faith in Jesus as the Son of God [underlining added]
Comfort, Philip W. 2008. New Testament Text and Translation Commentary: Commentary on the Variant Readings of the Ancient New Testament Manuscripts and How They Relate to the Major English Translations. Carol Stream, IL: Tyndale House Publishers, Inc.
Regarding Irenaeus' (c. 125 – c. 202 AD), the passage in which he writes about the encounter between Philip and the Ethiopian eunuch, does not quote Scripture, rather
Irenaeus expounds upon the story.
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.
Irenaeus of Lyons. 1885. “Irenæus against Heresies.” In The Apostolic Fathers with Justin Martyr and Irenaeus, edited by Alexander Roberts, James Donaldson, and A. Cleveland Coxe, 1:433. The Ante-Nicene Fathers. Buffalo, NY: Christian Literature Company.
There is nothing doctrinally incorrect with the added quotation: the additional words answer the question of exactly what did the eunuch profess to believe. The passage is just not in the majority of manuscripts.
The question then becomes whether this widely known quote from Irenaeus was incorporated into the Scriptures after Irenaeus wrote it.
The manuscript evidence is highly weighted toward omitting the verse.
Rob