I Thank God

Philippians 1:3-8

3 I thank my God in all my remembrance of you, 4 always offering prayer with joy in my every prayer for you all, 5 in view of your participation in the gospel from the first day until now. 6 For I am confident of this very thing, that He who began a good work in you will perfect it until the day of Christ Jesus. 7 For it is only right for me to feel this way about you all, because I have you in my heart, since both in my imprisonment and in the defense and confirmation of the gospel, you all are partakers of grace with me.
NASU

Action: Who was Paul thinking about while in prison? Why?