The Lutheran Epitome: Luther's 'purely passive' concerns the kindling of new motions
The teaching of the theologians of the Augsburg Confession comes to the same thing. 'Luther's statement,' they say, 'that man's will is purely passive in conversion must be taken in the right and proper sense: with respect to divine grace kindling new motions. It refers to the moment when God's Spirit, through the word heard or the use of the sacraments, takes hold of man's will and works conversion and regeneration in him.
Once the Holy Spirit has done and accomplished this, and has changed and renewed man's will by his divine power and working alone, then man's new will really is an instrument and organ of God the Holy Spirit: so that it not only lays hold of grace but also cooperates with the Holy Spirit in the works that follow.' Epitome of the articles in controversy among the theologians of the Augsburg Confession, article 2, on free choice.
Latin
XL. Et eodem quoque redit doctrina Theologorum confessionis Augustanae. Quod Lutherus, inquiunt, scripsit hominis voluntatem in conversione pure passive se habere, id recte & dextre est accipiendum, videlicet, respectu divinae gratiae in accendendis novis motibus: hoc est, de eo intelligi oportet, quando spiritus Dei per verbum auditum, aut per usum Sacramentorum hominis voluntatem aggreditur, & conversionem atque regenerationem in homine operatur. Postquam enim Spiritus Sanctus hoc ipsum jam operatus est, atque effecit, hominisque voluntatem sola sua divina virtute & operatione immutavit atque renovavit: tunc revera hominis nova illa voluntas instrumentum est & organum Dei Spiritus Sancti, ut ea non modo gratiam apprehendat, verum etiam in operibus sequentibus Spiritui Sancto cooperetur. In Epitome articulorum de quibus controversiae ortae sunt inter Theologos Confessionis Augustanae art. 2. qui est de libero arbitrio.