Acts 4:7

In the midst. The Sanhedrin sat in a semicircle (see Mishnah Sanhedrin 4. 3, Soncino ed. of the Talmud, p. 230). Apparently Peter and John were placed in the center.

By what power? Gr. en poia dunamei, “in what kind of power?” The word dunamis, “power,” used here, is often applied to Christ’s miracles, and frequently is rendered “mighty works” (see Matt. 11:20; Mark 6:14; Luke 19:37). The Jewish leaders admitted that the lame man had been healed by a marvelous manifestation of power; that was too obvious to deny (see on Acts 4:16). But their question implied a suspicion that it was the result of a power from below, an implication similar to the accusation once leveled against Jesus (see Luke 11:15; cf. John 8:48).

By what name? Or, “in what kind of name?” See on ch. 3:16. The Jewish leaders doubtless knew that it was in the name of Jesus that Peter and John had healed the lame man. To them, Jesus was a man who had recently been crucified as a criminal. Hence their disdainful question.