Paul begins 1 Corinthians by doing something he often does in his epistles: he mentions a co-worker.
"Paul, called by the will of God to be an apostle of Christ Jesus, and our brother Sosthenes, to the church of God which is at Corinth. . ." (1 Co 1:1–2).The question of Sosthenes' identity is an extremely interesting one. Is he the same figure who gets beaten in Acts 18? Is he the amanuensis of 1 Corinthians? Frankly, we just can't know the answers here.
What we do know though is nonetheless fascinating: Paul mentions him.
In fact, the letters attributed to Paul frequently include his co-workers in the opening addresses; they are thus listed as co-senders: Timothy, 2 Cor. 1:1; Phil. 1:1; Col 1:1; Phlm. 1; Silvanus (Silas) and Timothy in 1 Thess. 1:1 and 2 Thess. 1:1.
Why is this worth mentioning? Because this is almost unheard of!
As scholars such Anthony Thiselton and Ernest Richards explain, this hardly ever happens! The mention of a co-sender in the opening of an epistle is exceedingly unusual in ancient Greek letters outside of the Pauline corpus. In his book, The Secretary in the Letters of Paul (Tübingen: Mohr-Siebeck, 1993), Richards finds only six instances of this in 645 papyrus letters! [p. 47, n. 138].
So why does Paul include a mention of co-senders? I think Anthony Thiselton makes the best suggestion:
"Paul does not perceive himself as commissioned to lead or to minister as an isolated individual, without collaboration with co-workers." (The First Epistle to the Corinthians: A Commentary on the Greek Text [NIGTC; Grand Rapids: Eerdmans, 2000], 69).In short, Paul is an ecclesial thinker. Paul is a not a "lone ranger", but works as a member of the household of faith, the community of believers--he is one member of the Mystical Body of Christ, the Church.
As Paul explains later in 1 Corinthians,
For just as the body is one and has many members, and all the members of the body, though many, are one body, so it is with Christ. . . . Now you are the body of Christ and individually members of it. 28 And God has appointed in the church first apostles, second prophets, third teachers, then workers of miracles, then healers, helpers, administrators, speakers in various kinds of tongues. (1 Cor 12:12, 27–28).
Paul may be the "apostle" (1:1), but Sosthenes is a valued co-worker (a "helper?")--as such, he deserves mention as well.