A.T. Robertson Commentary Acts 5:40

"And to him they agreed: and when they had called the apostles unto them, they beat them and charged them not to speak in the name of Jesus, and let them go." — Acts 5:40 (ASV)

To him they agreed (επεισθησαν αυτω). First aorist passive indicative of πειθω, to persuade, the passive to be persuaded by, to listen to, to obey. Gamaliel's shrewd advice scored as against the Sadducaic contention (verse 17).

Not to speak (μη λαλειν). The Sanhedrin repeated the prohibition of 4:18 which the apostles had steadily refused to obey. The Sanhedrin stood by their guns, but refused to shoot. It was a "draw" with Gamaliel as tactical victor over the Sadducees. Clearly now the disciples were set free because only the Sadducees had become enraged while the Pharisees held aloof.