2 Timothy 1:3

Paul often talks about thanksgiving after the greeting section of his letters. While he is reminded of Timothy in his prayers, Paul thanks God. This is similar to how Paul was thankful to God for the believers at the church in Corinth in the beginning of 1 Corinthians. Paul refers to his ancestors or forefathers. His thankfulness or his serving is also what those before him have done. I guess this downplays himself and his actions, showing that there were men before him who tread a similar path. He also slips in "with a clear conscience", as if to further reassure himself or others about his own actions.