John Gill Commentary Acts 9:14

"and here he hath authority from the chief priests to bind all that call upon thy name." — Acts 9:14 (ASV)

And here he has authority from the chief priests
His fury and madness against the saints did not stop at Jerusalem, but he had received a commission from the sanhedrim to go to Damascus, where he now was:

to bind all that call on your name ;
to take up all such persons and put them in bonds, and carry them bound to Jerusalem, whom he should find either praying to Christ, as God, as the first Christians used to do, and which is no inconsiderable proof of the deity of Christ; or professing the name of Christ, or were called by it.