And the Lord said to Paul in the night by a vision, "Do not be afraid any longer, but go on speaking and do not be silent; for I am with you, and no man will attack you in order to harm you, for I have many people in this city."
Acts 18:9-10

The conversion of the important Jewish leader, Crispus (v.8), caused no small stir. Doubtless, the believers were excited and encouraged. But the unconverted Jewish community was most certainly not happy. This may have caused Paul to think that due to increased persecution he needed either to back off, or maybe even move on, as he did when persecuted at Thessalonica (ch.17). But the Lord wanted him to remain in Corinth and to keep preaching Christ and the gospel.

The Lord’s first words were “Do not be afraid.” These four words are among the most common uttered by the Lord to His people. Why? Because we are easily frightened, whether by life’s common trials, or as in this case, of persecution. Persecution is scary, whether it is physical (including martyrdom) or merely being ridiculed. Of course none of us wants to suffer physical persecution, but nearly all of us are also quite afraid of being poorly thought of or spoken of.

Regardless of the reasons for our fears, God’s most common words of comfort and encouragement are, “Do not be afraid.” Jesus weighed in on this matter most directly in Matthew 10:28.

And do not fear those who kill the body but cannot kill the soul. But rather fear Him who is able to destroy both soul and body in hell.

In other words: Do not fear people, but do fear God. Fearing God biblically, which includes trusting and loving Him, is the single most effective antidote for fearing people. After all, since the Lord loved us enough to give His life to save our souls, we can trust Him when we are tempted to fear people. (See Romans 8:31-39)