Even some TRINITARIAN Bibles render Acts 20:28, "to care for the church of God which he obtained with the blood of his own Son." - RSV, 1971 ed.; NRSV; NJB; (also see TEV and GNB).
The New Testament Greek words tou idiou follow "with the blood" in this scripture. This could be translated as "with the blood of his own." A singular noun may be understood to follow "his own." This would be referring to God's "closest relation," his only-begotten Son.
Famous trinitarian scholar J. H. Moulton says about this:
"something should be said about the use of [ho idios, which includes tou idiou] without a noun expressed. This occurs in Jn 1:11, 13:1; Ac 4:23, 24:23. In the papyri we find the singular used thus as a term of endearment to near relations .... In Expos. vi. iii. 277 I ventured to cite this as a possible encouragement to those (including B. Weiss) who would translate Acts 20:28 `the blood of one who was his own.'" - A Grammar of New Testament Greek, Vol. 1 (Prolegomena), 1930 ed., p. 90.
Highly respected trinitarian New Testament scholars Westcott and Hort present an alternate reason for a similar rendering:
"it is by no means impossible that YIOY [huiou, or `of the Son'] dropped out [was inadvertently left out during copying] after TOYIDIOY [tou idiou, or `of his own'] at some very early transcription affecting all existing documents. Its insertion [restoration] leaves the whole passage free from difficulty of any kind." - The New Testament in the Original Greek, Vol. 2, pp. 99, 100 of the Appendix.
(Also see A Textual Commentary on the Greek New Testament, p. 481)
Since so many respected trinitarian scholars admit the possibility (and even the probability) of such honest alternate non-trinitarian translations for Acts 20:28, this scripture can't honestly be used as proof for a trinity concept.
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