Of the Gospel and the Extent of the Grace Thereof (1689 LBCF, Chap. 20, Par. 4)

Although the Gospel is offered freely to all, not all accept it due to their being dead in sins and trespasses, until they are made alive and enabled by the Holy Spirit to answer this call. This quickening of the spirit is necessary for the sinner to truly come to Christ and be saved. Thus, the saving grace of the Gospel is not owing to the power of man to accept the call on his own but is entirely the work of the Holy Spirit, who makes the call effectual to those whom God has elected unto life.