2 Timothy 1:8

therefore--seeing that God hath given us such a spirit, not that of fear. Be not thou . . . ashamed--I agree with ELLICOTT, in opposition to ALFORD, that the Greek subjunctive here, with the negative, implies action completed at one time, not continued action, which the present imperative would express; thus implying that Timothy had not decidedly yet evinced such feeling of shame; though I think, Paul, amidst the desertion of others who once promised fair, and from being aware of Timothy's constitutional timidity (see on Ti2 1:7), felt it necessary to stir him up and guard him against the possibility of unchristian dereliction of duty as to bold confession of Christ. Shame (Ti2 1:8) is the companion of fear (Ti2 1:7); if fear be overcome, false shame flees [BENGEL]. Paul himself (Ti2 1:12), and Onesiphorus (Ti2 1:16), were instances of fearless profession removing false shame. He presents in contrast sad instances of fear and shame (Ti2 1:15). of the testimony of our Lord--of the testimony which thou art bound to give in the cause of our Lord; he says "our," to connect Timothy and himself together in the testimony which both should give for their common Lord. The testimony which Christ gave before Pilate (Ti1 6:12-13), is an incentive to the believer that he should, after His Lord's example, witness a good testimony or confession. nor of me his prisoner--The cause of God's servants is the cause of God Himself (Eph 4:1).

— Jamieson-Fausset-Brown Commentary (public domain)