Paul needed encouragement.  He needed his hope replenished.  He needed to endure and be bold and steadfast.  God assured him that he was already working in Corinth.

Acts 18:9-10 — for (1) I am with you, and (2) no one will attack you to harm you, (3)for I have many in this city who are my people.’ 

God has you in a strategic place where he is already working.  TAKE HEART.  Live in hope that God has his people and is using you to bring them into the family of God.