Albert Barnes Commentary Acts 9:29

"preaching boldly in the name of the Lord: and he spake and disputed against the Grecian Jews; but they were seeking to kill him." — Acts 9:29 (ASV)

He spoke boldly. He openly defended the doctrine that Jesus was the Messiah.

In the name, etc. By the authority of the Lord Jesus.

Against the Grecians. See the explanation of the word Grecians in the notes on Acts 6:1.

This means that he not only maintained that Jesus was the Christ in the presence of those Jews who resided at Jerusalem and spoke the Hebrew language, but also before those foreign Jews (often called Hellenists) who spoke the Greek language and had come up to Jerusalem. They would be as much opposed to the doctrine that Jesus was the Christ as those who resided in Jerusalem.

They went about. They sought to kill him; or they formed a purpose or plan to put him to death as an apostate. See Acts 9:23.