Charles Ellicott Commentary Acts 8:37

"[And Philip said, If thou believest with all thy heart, thou mayest. And he answered and said, I believe that Jesus Christ is the Son of God.]" — Acts 8:37 (ASV)

And Philip said. . . .—The verse is a striking illustration of the tendency that appeared at a very early period to improve the text of Scripture with a view to greater edification. It existed in the time of Irenæus, who quotes it (3:12), but is missing from all the best manuscripts, including the Sinaitic, and many versions. The motive for the interpolation lies on the surface. The abruptness of the unanswered question, and the absence of the confession of faith that was required in the Church’s practice for the baptism of every convert, seemed likely to be stumbling-blocks, and the narrative was completed according to the accepted form of the prevailing order for baptism. Even with the insertion, the shortness of the confession points to a very early stage of liturgical development, as does the reference to it in Irenæus.