My limited experience as a translator has taught me that one should acquaint oneself with a book before attempting to give an accurate translation of it.

The lack of familiarity with the content of the material can lead to errors.

Today I was skimming through the French translation of the commentary on Isaiah written by Theodoret of Cyrus.

It seems to me that by the festival τῶν ἑβδομάδων Theodoret means “the festival of the weeks”, not the Sabbath, as J.N. Guinot understands the text. It would make more sense to take τὴν τοῦ πάσχα, τὴν τῶν ἑβδομάδων, τὴν τῶν σκηνῶν as referring to the three big “pilgrimage festivals”: Pesach (Passover), Shavuot (Weeks), and Sukkot (Tents or Booths).

Below you can read the French translation and the Greek text.

theodoret(Τὰς νεομηνίας ὑμῶν) καὶ τὰ σάββατα καὶ ἡμέραν μεγάλ(ην οὐκ) ἀνέχομαι, (νηστείαν καὶ ἀργίαν) 14καὶ τὰς ἑορτὰς ὑμῶν μισεῖ ἡ ψυχή μου. ᾿Ιδοὺ καὶ τὰς πολυθρυλήτους |98 a| (ἐξέβαλεν) ἑορτάς· τὴν τοῦ πάσχα, τὴν τῶν ἑβδομάδων, τὴν τῶν σκηνῶν καὶ πρὸς τούτοις (τὴν τῶν) σα(λπίγ)γων, τὴν τοῦ ἱλασμοῦ. ῾Ημέραν γὰρ μεγάλην τὰς μεγάλας ἑορτὰς ὀνομάζει, νηστείαν δὲ τὴν τ(οῦ ἱ)λα(σμοῦ) ἡμέραν. Καὶ καθολικῶς πᾶσαν ἑορτὴν καὶ πᾶν σάββατον μεμισηκέναι  φησίν. Καὶ τὴν αἰτίαν διδάσκει·