1 Corinthians 16:5

Now I will come unto you, when I shall pass through Macedonia: for I do pass through Macedonia (KJV)

Then: In this and the next four verses, Paul talks about his travel plans. He must have raised the hopes of many who read and heard the letter. Specifically he's heading to Macedonia and Corinth is logically part of that trip.

Now: Paul's travel plans are of historical interest in understanding Paul's life and ministry. Paul expected to leave Ephesus (Wright, p. 230 says midsummer), head north and go through the top part of Greece, then circle back down to come through Corinth.