12 Therefore, my beloved, as you have always obeyed, so now, not only as in my presence but much more in my absence, work out your own salvation with fear and trembling, 13 for it is God who works in you, both to will and to work for his good pleasure(Phil. 2:12-13)
"For this I toil, struggling with all his energy that he powerfully works within me"(Col. 1:28).
Many Calvinists are afraid to describe sanctification as monergistic because they believe it means imperatively that we should not do anything, but instead just sit around until God works. This is not what monergistic sanctification entails. Rather, it is the indicative that whenever we do work (and we certainly are obligated to work) the initiative is of God in sanctification just as it is in initial justification. This no more entails that we do not have to work than monergism in saving faith entails that we do not have to believe, as some Arminians have absurdly accused us of teaching. As we see in the above quotes, the Christian is to work witih all his might, and the only reason we can do so is because God works it in us by His Spirit. Synergism in sanctification has the same danger that it does in initial saving faith: It threatens to make our decision to cooperate with God's grace contingent on the decision of our autonomous wills, rather than on God's grace and absolute predestination. On the contrary, whenever we choose to "cooperate" with God's grace, or obey God at all, it is only because God has wrought it in us antecedently.