Acts 20:28 W&H
Georg Luck:προσέχετε ἑαυτοῖς καὶ παντὶ τῷ ποιμνίῳ, ἐν ᾧ ὑμᾶς τὸ πνεῦμα τὸ ἅγιον ἔθετο ἐπισκόπους, ποιμαίνειν τὴν ἐκκλησίαν τοῦ θεοῦ, ἣν περιεποιήσατο διὰ τοῦ αἵματος τοῦ ἰδίου
And from a footnote:In his farewell speech to the elders of the congregation in Ephesus, Paul says: “So keep watch over yourselves and the whole flock which the Holy Spirit has placed in your care, so you are shepherds of the church of God which he has made through his own blood.” Can we really accept the readings αἵματος τοῦ ἰδίου or ἰδίου αἵματος? The NJB very sensibly translates “the Church of God which he bought with the blood of his own Son,” adopting a conjecture by Knapp, without giving him credit. As Knapp recognized, υἱοῦ was omitted by mistake after ἰδίου by haplography, because of the similarity of the capital letters. In Rom. 8:32 we actually read τοῦ ἰδίου υἱοῦ. That God shed his own blood cannot possibly be the meaning of the Greek, because τοῦ ἰδίου is postponed, nor can God’s own blood” mean “God’s own son”, because “blood” is never used for “son” in the Book of Acts. On the other hand, the idea that God made the Church his own by the blood of Jesus is central to Paul’s thought. A rather desperate way out of the difficulty has been proposed by Metzger who supposes that ὁ ἰδίος could be a title for the Messiah, like ὁ ἀγαπητός. Along the same lines, J. Jervell takes ἰδίου as “of his own”, i. e. Christ which seems to do violence to Greek.
See on this and other controversial passages H. Riesenfeld, “Sind Konjekturen bei einer Übersetzung des Neuen Testaments notwendig?”, in: Text-Wort-Glaube, Kurt Aland gewidmet, ed. by M. Brecht (=Arbeiten zur Kirchengeschichte 50, 1989), 40-6. Riesenfeld, a theologian, and J. Palm, a hellenist, were commissioned by the Swedish government to translate the New Testament into Swedish. They decided to approach textual problems in a pragmatic fashion, by looking critically, as they say, at all conjectures found in editions and commentaries. They also focused on obscure passages, keeping in mind the possibility of textual corruption. In the end, they claim to have found only two passages, Col. 2:23 and Jude 22-3 which, in their opinion, were corrupt, no satisfactory conjectures being available. In these two instances, they chose a variant from the paradosis and proposed a translation which, in their own words, did not sound “totally nonsensical” – a modest goal, to be sure, though I have doubts about the validity of their method. In two passages, the one we are discussing now and in Rom. 4:11-2, they considered adopting a conjecture but felt that it was not absolutely necessary. In Acts 16:12 (see above) they believed that the conjecture was “highly probable”. In Rom.7:21, Riesenfeld proposed a conjecture of his own. Needless to say, these results give a completely misleading picture of the actual situation. To eliminate suggestions made by scholars like Scaliger, Grotius or Bentley and then surprise the world with a new one is not exactly an approach that deserves to be imitated.