John Robbins: Works are not the condition, ground, or instrument of salvation, but rather salvation is the condition or ground of obedience

"But the Holy Spirit speaking in Scripture ... repeatedly exhorts believers to lead holy lives. His argument is, You are already Christians; you have already passed from death to everlasting life; you are already saved; therefore, act like Christians. ... (Ephesians 5:8, 15-16). There are dozens of other such exhortations. But our acting like Christians does not save us, for we are already saved. The indicative -- salvation -- logically and chronically precedes the imperative: Behave as the saved people you are. Our good works are not the condition or ground or instrument of our salvation; our salvation is the condition or ground of our obedience. Works and justification are not related as equals, but as effects to cause. Ideas have consequences. Christian ideas have Christian consequences. Those who believe the Gospel, given the opportunity, will produce good works."

(John Robbins, Not Reformed at All: Medievalism in "Reformed" Churches, pp. 121-122)