Acts 6:7
And the word of God increased;
and the number of the disciples multiplied in Jerusalem greatly;
and a great company of the priests were obedient to the faith.

This has long seemed to me to be a reference by Luke to his own actions as well.

Here is Rick Strelan, from Luke the Priest.

Overall, the opposition to the apostles is from the chief priests, the elders, and Sadducees. While it is persistent throughout Luke’s narrative, their opposition is somewhat muted. In the end, it is not the opposing plans and scheming of the rulers, but the plan of God that interests Luke and that brings about the final destination and destiny of Paul. There is certainly no indication that the run-of-the-mill priests opposed the apostles.

On the positive side, as noted, there is one statement in Acts indicating that some priests associated with the Jesus movement. Luke says, ‘a great crowd of the priests were obedient to the faith' (Grk), Acts 6:7). The context suggests these were priests in Jerusalem. I take this as an indication that Luke had some sympathy for the common priests, and it might suggest that he himself belonged to that group. It is probably not coincidental that having made this statement, Luke immediately continues with the Stephen cycle in his narrative. We are probably supposed to think of Stephen as being one of those priests. In what follows in Acts 6-7, there is nothing that would gainsay that suggestion, and a few things that might support it. Stephen, like the priests of Israel, obviously knows the tradition and can recall and relate it: but not only does he retell it. he interprets it. He is not reprimanded by his superiors in the Sanhedrin (which included priests) for doing something he had no authority to do. He was a legitimate controller and ‘owner’ of the tradition. In that way, then, Stephen is like the writers of Jubilees and of the Testament of Levi. both most likely priests. He is also not dissimilar to Josephus, another priest. p. 126-127