Stephen"s declaration amounted to blasphemy to the Sanhedrin. They knew that when he said "Son of Man" he meant "Jesus." Furthermore, the Jews believed that no one had the right to be at God"s right hand in heaven. [1] The Sanhedrin members therefore cried out in agony of soul, covered their ears so they would hear no more, and seized Stephen to prevent him from saying more or escaping. Stoning was the penalty for blasphemy in Israel ( Leviticus 24:16; Deuteronomy 17:7), and the Sanhedrin members went right to it. [source][source][source]
In the three trials before the Sanhedrin that Luke recorded thus far, the first ended with a warning ( Acts 4:17; Acts 4:21), the second with flogging ( Acts 5:40), and the third with stoning ( Acts 7:58-60). The Sanhedrin now abandoned Gamaliel"s former moderating advice ( Acts 5:35-39). It did not have the authority to execute someone without Roman sanction, and Jewish law forbade executing a person on the same day as his trial. [2] However since witnesses were present to cast the first stones, as the Mosaic Law prescribed, Stephen"s death seems not to have been simply the result of mob violence but official action. Probably it was mob violence precipitated and controlled by the Sanhedrin along the lines of Jesus" execution. [source][source][source]
"The message of Stephen, it seems, served as a kind of catalyst to unite Sadducees, Pharisees, and the common people against the early Christians." [3][source]
Saul of Tarsus was there and cooperated with the authorities by holding their cloaks while they carried out their wicked business (cf. Acts 8:1; Acts 22:20). He was then a "young man" (Gr. neanias, cf. Acts 20:9; Acts 23:17-18; Acts 23:22), but we do not know his exact age. Since he died about A.D68 and since Stephen probably died about A.D34 , perhaps Saul was in his mid-thirties. Jesus and Saul appear to have been roughly contemporaries. This verse does not imply that Saul was a member of the Sanhedrin. [4][source]