A.T. Robertson Commentary Acts 18:4

"And he reasoned in the synagogue every sabbath, and persuaded Jews and Greeks." — Acts 18:4 (ASV)

He reasoned (διελεγετο). Imperfect middle, same form as in 17:17 about Paul's work in Athens, here only on the Sabbaths.

Persuaded (επειθεν). Imperfect active, conative, he tried to persuade both Jews and Greeks (God-fearers who alone would come).