“Arminius’ views clearly belong to the category of those of Karg and Piscator: he not only attributes no soteriological purpose to Christ’s active obedience, he also restricts the purpose of the nominally passive aspects of Christ’s obedience in life and ministry to a preparatory testing of the Mediator. In addition, Arminius, like Karg, had modified the protes tant scholastic doctrine of a purely forensic imputation of Christ’s righteousness by arguing the necessity of active obedience on the part of believers. As in the satisfaction-theory of the medieval doctors, the distinction between a salvific passive obedience of Christ and a non-salvific active obedience points in the theology of Arminius toward a doctrine of human involvement or cooperation in the work of salvation. In other words, Arminius’ separation of Christ’s active and passive obedience in his christological locus correlates with his soteriological synergism.”
Richard A. Muller, “The Christological Problem in the Thought of Jacobus Arminius,” Nederlands Archief voor Kerkgeschiedenis 68–2 (1988), 157 (HT: Inwoo Lee).