2 Timothy 1.8
ESV "the testimony about our Lord" The ;hrase emphasizes the testimony borne, the message itself.
Prisoner .. Not of Caesar, but of Christ! Ephesians 3:1; Ephesians 4:1; Philemon 1:9 .
Paul considered it the will of God that he should suffer.
Be not ashamed.. doesn't mean that Timothy was. Gk present imperative with the negative forbids an action already going on. Here the aorist subjunctive with the negative forbids an act not yet begun. (Wuest).
Partaker = "share in suffering for the gospel". This sharing could have resulted in Timothy's imprisonment, cf Hebrews 13:23. [From the tone of Paul's words it appears that Timothy's imprisonment may have been after this writing. My speculation is that Timothy went to Rome to see Paul as he requested, was imprisoned also with him, but probably because his father was not a Jew, he was released. This was a time of great anamosity against both Jews and Christians on the part of the Romans.]
Every Christian should know that Christianity doesn't promise an easy, convenient, popular or man-pleasing couse of action, but the readiness to suffer for adhering to the gospel is the will of God.
Problem: the sorm of imperial opposition to Christiany following Nero's false charges caused powerful friends of Paul in Asia, such as the Asiarches of Ephesus ( Acts 19:31) to find it very difficult and political suicide to support Paul in his appearance before Nero's court. Timothy was not to be influenced by such shameful and cowardice action.