David Platt
The martyrs did not die because they believed the gospel. They died because the proclaimed the gospel.

The flesh and blood of Christ are not less truly given to the unworthy than to the elect believers of God; and yet it is true, that just as the rain falling on the hard rock runs away because it cannot penetrate, so the wicked by their hardness repel the grace of God, and prevent it from reaching them.
John Calvin