When we were all fallen (pantōn katapesontōn hēmōn). Genitive absolute with second aorist active participle of katapiptō. In the Hebrew language (tēi Ebraidi dialektōi). Natural addition here, for Paul is speaking in Greek, not Aramaic as in Act 22:2.
It is hard for thee to kick against the goad (sklēron soi pros kentra laktizein). Genuine here, but not in chapters 9, 22. A common proverb as Aeschylus Ag. 1624: Pros kentra mē laktize. “It is taken from an ox that being pricked with a goad kicks and receives a severer wound” (Page). Cf. the parables of Jesus (Mat 13:35). Blass observes that Paul’s mention of this Greek and Latin proverb is an indication of his culture. Besides he mentions (not invents) it here rather than in chapter 22 because of the culture of this audience. Kentron means either sting as of bees (II Macc. Act 14:19) and so of death (1Co 15:55) or an iron goad in the ploughman’s hand as here (the only two N.T. examples). Note plural here (goads) and laktizein is present active infinitive so that the idea is “to keep on kicking against goads.” This old verb means to kick with the heel (adverb lax, with the heel), but only here in the N.T. There is a papyrus example of kicking (laktizō) with the feet against the door.