Most of the examples of Origen’s text-critical observations occur in the Gospels, but I have found one in Acts. In commenting on Acts 13:33, Origen notes that Acts attributes Psa 2:7 to the first psalm (ὡς γὰρ γέγραπται φήσιν ἐν πρώτῳ ψαλμῷ) as does Codex Bezae (D), however, all other extant MSS of Acts refers to the second psalm (καὶ ἐν τῷ ψαλμῷ γέγραπται τῷ δευτέρῳ). After pointing out this discrepancy, Origen discusses the different numbering systems used by the Hebrew OT, in which Psalms 1 and 2 are considered separate compositions, while Acts 13:33 (apart from D) knows Psalm 1 and 2 as a single psalm (τὰ Ἑλληνικὶ μέντοι ἀντίγραφα δεύτερον εἶναι τοῦτον μηνεύει. τοῦτο δὲ οὐκ ἀγνοητέον ὅτι ἐν τῷ Ἑβραϊκῷ οὐδενὶ τῶν ψαλμῶν ἀριθμὸς παράκειται πρῶτος εἰ τύχοι ἢ δεύτερος ἢ τρίτος). While this is one of the few places where Origen agrees with D alone, Origen’s comment gives evidence that at Acts 13:33 “ἐν πρώτῳ ψαλμῷ” was present in some Greek MSS in the early third century.
 PS.CAT – 1099/1100, D2 is a catena and as such may not necessary reflect the exact text of Origen. 05 reads τω πρωτω ψαλμω γεγραπται.
 The Latin is “… verum exemplaria Graeca hunc secundum esse indicant illud autem non ignorandum est in Hebraieis exemplaribus nulli psalmo numerum apponi sive primus sive secundus sive tertius sit.” On the numbering of Psa 1 and 2, see Peter C. Craigie, Psalms 1–50 (WBC 19; Waco: Word Books, 1983), 18–19, who misreads the case when he writes, “The evidence from the early Christian tradition is found in Acts 13:33. The writer, Luke, gives a quotation from Ps 2:7, but introduces it as coming from the first psalm; the corrections, both in the early Greek text and in modern English versions, to read ‘the second psalm,’ are appropriate given the change in the conventional system of numbering the Psalms. Nevertheless, the oldest Greek text of Acts provides evidence for the early Christian view that the first two psalms were considered to be a single unit.” Actually, only D among extant Greek MSS, has ἐν πρώτῳ ψαλμῷ.