…to feed the church of God, which he hath purchased with his own blood. – Acts 20:28
In this place, the word “God” might possibly be understood of Christ, in like manner as in John 1:1. But the best and most ancient copies read it, and the most ancient Fathers cite it, “the Church of the Lord:” And therefore that is probably the true reading. Or, if the word “God” be understood to mean the Father; (which, if that reading be allowed, is the most natural interpretation;) then, “his own blood,” must signify, the blood of his own Son. Or lastly, supposing, (as before) that the word “God” is genuine, and signifies the Father; still the following words, “he hath purchased with his own blood,” may be understood of Christ, in the same manner of speaking that we find used in Luke 1:16-17. Not much unlike to which, is the expression John in his first epistle frequently uses, and particularly 1 John 3:5, “And ye know that HE was manifested to take away our sins; and in HIM is no sin:” Where the words “he,” and “him,” must of necessity be referred to Christ, though without any antecedent mention of him, the Father only having been before spoken of, Ver. 1, “Behold, what manner of love the FATHER hath bestowed upon us, &c.” And the same seems to be the true construction of those words, Ver. 16, “Hereby perceive we the love of GOD, because [ἐκεῖνος] he (viz. Christ) laid down his life for us:” which Paul expresses more fully, Rom. 5:8, “God commendeth his love towards us, in that, while we were yet sinners, CHRIST died for us.”1
Source: The Scripture Doctrine of the Trinity (Third Edition)
Note: Updated archaic spelling, capitalization, italics, etc.