For we preach not ourselves (ου γαρ εαυτους κηρυσσομεν). Surely as poor and disgusting a topic as a preacher can find.

But Christ Jesus as Lord (αλλα Χριστον Ιησουν Κυριον). Κυριον is predicate accusative in apposition.

As your servants for Jesus' sake (δουλους υμων δια Ιησουν). Your bond-slave for the sake of Jesus. This is the sufficient reason for any preacher's sacrifice, "for Jesus' sake."