1 Corinthians 1:16 - Ellicott's Commentary On The Whole Bible

Stephanas. — The mention of Stephanas and his household was, from the words preceding, evidently a subsequent correction by the Apostle. He had forgotten them, and was reminded of it possibly by Sosthenes, who was writing from his dictation, and would naturally have known the fact, for Stephanas was the “firstfruits of Achaia” (1 Corinthians 16:15), and Sosthenes had been chief ruler of the synagogue (Acts 18:17) when Paul had been brought before Gallio, deputy of Achaia. Stephanas himself was at Ephesus with St. Paul when this letter was written, and doubtless in daily intercourse both with him and with Sosthenes (1 Corinthians 16:17). Finding how his memory had failed him on this point, the Apostle adds, “And I know not,” &c. (i.e., I don’t remember) so as to prevent any cavil from hypercritical opponents.