1 Corinthians 16:5

But. will come unto you, when. shall have passed through Macedonia; for. pass through Macedonia;

'I will come unto you' -a detail that he has already mentioned in this letter. (1 Corinthians 4:18-19) In fact, earlier Paul had said that he was coming "soon" (1 Corinthians 4:19). Paul often mentions his travel plans to congregations and individuals. (Romans 15:22; 1 Peter 2:24; Philemon 1:22; Titus 3:12)

'when. shall have passed through Macedonia' -when this letter was being written Paul was in Ephesus (1 Corinthians 16:8). According to this verse, he wasn't going to take the direct route (by sea), rather he would take the overland route, which would involve. journey through Macedonia (coming down from the north-look at. map).

'for. pass through Macedonia' -(Acts 19:21) 'This verb is used frequently in Acts to describe missionary activity in places where they did not stay an extended period of time (cf. 1 Corinthians 8:4: 1 Corinthians 11:19; 1 Corinthians 13:6)' (Fee p. 818)

After leaving the Macedonian region on his second journey, Paul had spent over 18 months in Corinth (Acts 18:11; Acts 18:18) and three years in Ephesus (1 Corinthians 19:10; 1 Corinthians 20:31). Hence, it had been about five years since Paul had visited congregations in Macedonia (Philippi, Thessalonica, and Berea).