If you look back at verse 3, though (Perhaps they will listen and each will turn from his evil way. Then I will relent and not bring on them the disaster I was planning because of the evil they have done.), you will see that this all occured on the basis of a "perhaps". God told Jeremiah that if he would stand up once again and speak these things, then "perhaps" the others would change their ways.
In Christian circles we often talk about the necessity to be willing to be martyred for our beliefs. To be willing to die for Christ is really a necessary part of our walk. To be willing to come forward and shout our faith and bring others to Christ ... that is all part of the call.
But we must ask ourselves, are we really all that willing ... even for a "perhaps"? How often have I chosen to ignore even very simple opportunities to share my faith or to show Jesus' love? And in completely non-threatening circumstances. How often am I too caught up in my "self" to be willing to go to the wall for Jesus? And especially if it's "just" for a "perhaps"?