Friends, this is the best i have ever read on this topic. I am studying 2 Timothy right now and this is part of John Calvin's commentary on chapter 3. (For the entire commentary read here) v.12 Indeed all who wish to live a godly life in Christ Jesus will be persecuted...
"And he says this, partly that believers may prepare themselves for submitting to this condition, and partly that good men may not view him with suspicion on account of the persecutions which he endures from wicked persons; [think JOB] as it frequently happens that the distresses to which men are subjected lead to unfavorable opinions concerning them... immediately declared by the common people to be hated by God.
By this general statement, therefore, Paul classes himself with the children of God, and, at the same time, exhorts all the children of God to prepare for enduring persecutions; for, if this condition is laid down for “all who wish to live a godly life in Christ,” they who wish to be exempt from persecutions must necessarily renounce Christ. my favorite part of the whole thing: In vain shall we endeavor to detach Christ from his cross; for it may be said to be natural that the world should hate Christ even in his members. In short, let us know that we are Christians on this condition, that we shall be liable to many tribulations and various contests.
But it is asked, Must all men be martyrs? for it is evident that there have been many godly persons who have never suffered banishment, or imprisonment, or flight, or any kind of persecution. I reply, it is not always in one way that Satan persecutes the servants of Christ. But yet it is absolutely unavoidable that all of them shall have the world for their enemy in some form or other, that their faith may be tried and their steadfastness proved; for Satan, who is the continual enemy of Christ, will never suffer any one to be at peace during his whole life; and there will always be wicked men that are thorns in our sides. Moreover, as soon as zeal for God is manifested by a believer, it kindles the rage of all ungodly men;accordingly, although they are not exposed to the same assaults, and do not engage in the same battles, yet they [the persecuted non-martyrs] have a warfare in common, and shall never be wholly at peace and exempt from persecutions.