E. P. Sanders’ Paul and Palestinian Judaism was instrumental in sparking the discussion about Pauline theology that has dominated New Testament studies in the last generation. Though Sanders’ critique of Schweitzer is on point, Sanders acknowledges the participationist language Paul employs, especially with regard to suffering. For example, part-and-parcel with what Sanders describes as “transfer to being a Christian” is “participation in the death of Christ.” Indeed, Sanders summarizes: “the main theme of Paul’s gospel was the saving action of God in Jesus Christ and how his hearers could participate in that action.” 
To be sure, Sanders does go on to say, “the principal word for that participation is ‘faith’ or ‘believing’, a term which Paul doubtless took over from the earlier Christian missionaries” but Sanders also points out repeatedly that participation in Christ’s suffering and death is requisite to being “in Christ” and participating in the resurrection. Sanders makes this explicit in his discussion of Pauline righteousness in relation to participation where he points out that participation in Christ in the form of sharing in Christ’s sufferings is “how one attains the resurrection.”
Later in that same discussion Sanders writes that Paul “tells us over and over again: the goal of religion is ‘to be found in Christ’ and to attain, by suffering and dying with him, the resurrection.”
In Sanders’ conclusion to this same section, Sanders concludes that the true righteousness from God “which depends on faith […] is received when one is ‘found in Christ’, shares his suffering and is placed among those who will share his resurrection.”
One further point from Sanders is important to point out. Sanders notes that “Paul does not have one fixed terminology for participation” and concludes that “the very diversity of the terminology helps to show how the general conception of participation permeated his thought.” This means that, first of all, that since participation permeates Paul’s thought we ought reasonably to expect that participation permeates his thoughts on suffering, as well. It also means that we must be careful not to limit discussion of participatory suffering in Paul to passages that employ only certain key terms or phrases, but must be on the lookout for places where Paul discusses such participation in suffering apart from those terms. Indeed, given the diversity Sanders notes, it is reasonable to assume that Paul will discuss participation and suffering employing a variety or terms and phrases.
“But more important—and this is basically what is wrong with Schweitzer’s theory as a whole—Schweitzer did not see the internal connection between the righteousness by faith terminology and the terminology about life in the Spirit, being in Christ and the like (terminology which here will be called ‘participationist’, which seems better than the controversial term ‘mystical’), a connection which exists in Paul’s own letters.” Sanders, PAPJ, 440.