Paul has just recounted a very dark time in his life to the Corinthian church. He has spoken of His despair and of the God who raised him from death's gloom and taught him to trust. He has reminded them to set their hope on the God of hope and to rest in His deliverance. He has also called them to prayer.
That's important and we need not miss it. Paul has had "the sentence of death within himself". He has hurt. He has suffered. The Father of Christ has saved the day and one of the means He has used in doing so has been the prayers of God's people.
Obviously Paul is sharing these things with Corinth because they are suffering. He has been pointing them to the God of all mercy and comfort. He has been challenging them to consider that the comfort which they will receive is to be shared with others. He is reminding them that the God who delivered him will deliver them. And...he's pushing them to pray.
The greatest thing we can offer for one who is suffering is our prayers. Are we offering that? Are you standing in the gap for those who are desparing? If no, then start. If yes, then continue knowing that in due time you will reap the opportunity of giving thanks for God's answers.