Christ, in this vision, useth two arguments to persuade Paul to continue preaching the gospel at Corinth:
1. Because he would be with him, to supply, support, and deliver him; as it is promised to Jeremiah, Jeremiah 1:19, and to all the faithful ministers of Christ, Matthew 28:20. This promise was fulfilled to Paul, and to other of God's servants; whatsoever troubles they met with, even when they were killed, they were not hurt, Romans 8:36-39.
2. The other reason why Paul was commanded to tarry was, because there were many that God would have called by his ministry; and thus those who were not his people God calleth his people, as Hosea 1:10, Hosea 2:23.