Jamieson, Fausset and Brown on 2 Timothy 2:9

9. Wherein--in proclaiming which Gospel.

suffer trouble--literally, "evil." I am a sufferer of evil as though I were a doer of evil.

bonds--(2Ti 1:16).

word ... not bound--Though my person is bound, my tongue and my pen are not (2Ti 4:17; Ac 28:31). Or he alludes not merely to his own proclamation of the Gospel, though in chains, but to the freedom of its circulation by others, even though his power of circulating it is now prescribed (Php 1:18). He also hints to Timothy that he being free ought to be the more earnest in the service of it.