These are all good points. In the book I read the author made the claim that our suffering is a way of spreading the gospel and helps complete Christs suffering and told of many examples of people who gave themselves up to be martyred or beaten for the sake of the gospel and as a result people were converted.
I rest my case. Christ's suffering is complete in itself. Our suffering adds nothing to Christ's work.
Yes, and many twist Colossians 1:24 to say this.
But this verse STILL needs to be dealt with:
24Who now rejoice in my sufferings for you, and fill up that which is behind of the afflictions of Christ in my flesh for his body's sake, which is the church:
John Piper (Desiring God: Meditations of a Christian Hedonist, 2003) says this:
"Paul's sufferings, complete Christ's afflictions not by adding anything to their worth, but by extending them to the people they were meant to save. What is lacking in the afflictions of Christ is not that they are deficient in worth, as though they could not sufficiently cover the sins of all who believe. What is lacking is that the infinite value of Christ's afflictions is not known and trusted in the world. . . . So the afflictions of Christ are 'lacking' in the sense that they are not seen and known and loved among the nations. They must be carried by the ministers of the Word. And those ministers of the Word 'complete' or 'fill up' what is lacking in the afflictions of Christ by extending them to others" (268).
On page 269:
"God intends for the afflictions of Christ to be presented to the world through the afflictions of His people. . . . Our calling is to make the afflictions of Christ real for people by the afflictions we experience in bringing them the message of salvation. Since Christ is no longer on the earth, He wants His body, the church, to reveal His suffering in its suffering"
http://www.desiringgod.org/ResourceLibrary/sermons/bydate/1992/806_Called_to_Suffer_and_Rejoice_To_Finish_the_Aim_of_Christs_Afflictions/
Understood this way, THERE IS something lacking in Christ's suffering - it's appointed presentation to the world, which we are appointed to perform.
17From now on let no one cause me trouble, for I bear on my body the marks of Jesus. (Galatians 6:17 ESV)