The focus of chapter 4 is encouragement through trials. Paul uses his ministry and partners as an example of perseverance.

vs 3&4 explain that Satan hides the understanding of the gospel is hidden from those who aren't ready to accept.

v 7 says trials show our power is from God

v 17 says trials are momentary

v 18 says we should focus on what He is going to do for us (the unseen) rather than the present or what we can see or imagine.

2 Corinthians 4:3-4, 2 Corinthians 4:7 and 2 Corinthians 4:17-18