But when [the Jews] resisted and reviled him, he shook out his garments and said, “Your blood be upon your own heads—I am clean! From now on, I will go to the Gentiles.”
Acts 18:6 TLV

Now the Lord said to Paul through a vision in the night, "Do not be afraid, but speak and do not be silent!"
Acts 18:9 TLV

It seems to me that God was correcting Paul's statement in v6 and encouraging him to continue to talk to the Jews although his primary mission was to the Gentiles.