Lutheran Epitome of Formula of Concord on conversion

http://www.bookofconcord.org/fc-ep.html#II.%20Free%20Will.

17] But, on the other hand, it is correctly said that in conversion God, through the drawing of the Holy Ghost, makes out of stubborn and unwilling men willing ones, and that after such conversion in the daily exercise of repentance the regenerate will of man is not idle, but also cooperates in all the works of the Holy Ghost, which He performs through us.

18] 9. Also what Dr. Luther has written, namely, that man's will in his conversion is pure passive, that is, that it does nothing whatever, is to be understood respectu divinae gratiae in accendendis novis motibus, that is, when God's Spirit, through the Word heard or the use of the holy Sacraments, lays hold upon man's will, and works [in man] the new birth and conversion. For when [after] the Holy Ghost has wrought and accomplished this, and man's will has been changed and renewed by His divine power and working alone, then the new will of man is an instrument and organ of God the Holy Ghost, so that he not only accepts grace, but also cooperates with the Holy Ghost in the works which follow.

19] Therefore, before the conversion of man there are only two efficient causes, namely, the Holy Ghost and the Word of God, as the instrument of the Holy Ghost, by which He works conversion. This Word man is [indeed] to hear; however, it is not by his own powers, but only through the grace and working of the Holy Ghost that he can yield faith to it and accept it.