In Ephesus we see that Paul spent a not-inconsiderable amount of time teaching in the synagogue (v.8). This was no aggressive conversion mission, more a man reasoning and persuading them about the kingdom of God. Paul spoke boldly and no doubt used Scripture at every junction (cf. 18.28).
However, when some became stubborn and continued in unbelief..he withdrew from them and took the disciples with him. Paul leaves because, simply, the Word of God was being stubbornly refused. He moved on to a borrowed school hall (v.9b) and preached for around five hours daily whilst people rested from work. We read that this continued for two years and that the fruit of his labour, and other’s too, was that all the residents of Asia heard the word of the Lord (cf. Ephesians 4.11-12).
Paul here shows us that it is ok to move on if the work has gone as far as it can go.
Rather than toil endlessly in a situation that is clearly not ordained of God to bear fruit (v.9) it’s ok to move on and to leave. There need be no feelings of guilt or abandonment if you have tried, repeatedly, to share the Good News only to have it rejected. Jesus said as much in Matthew 7.6 and I read recently that
“Repeatedly sharing the gospel with someone who continually scoffs and ridicules Christ is like casting pearls before swine”.
In moving on Paul shows us that it’s ok to leave a situation wherein it’s clear that there will be no progress.
How do we know if we are in a situation like that? Pray, read Scripture and see prior examples, and talk to godly, Spirit-filled believers in your life that you trust. If the conclusion is consistent, moving on is ok. Had Paul not then who knows if all the residents of Asia would have heard the word of the Lord. Don’t stay and stagnate if God is calling you elsewhere!