Defense and Opponents:
Paul's final words seemingly run contrary to our human nature and in fact the concept that some have of modern Christianity. Notice, "he has graciously granted you the privilege not only of believing in Christ, but of suffering for him as well—" (vs. 29) For Paul these words were not sterile or just smooth sayings. In fact, for Paul suffering for Christ is the struggle he enjoyed even while writing this letter..."the same struggle"..."that I still have." (vs. 30).
Paul is saying that those who war and struggle against the Gospel evidence their destruction. For those who seek God this sign also speaks of our salvation. The Psalmist declared something similar: "Fools say in their hearts, “There is no God.” (Psalms 14:1) The "fools" here are those who have no sense of morality or even social obligations (see Isaiah 32:6, I Samuel 25:25). They are corrupt and spiritually vile. They do not care for their lives and therefore do not seek God.