Lutheran John Gerhard (1582-1637), regarded as the greatest living theologian of Protestant Germany, writes of the Scriptures,
That the word itself has power to convert Gerhard finds an unambiguous doctrine of Scripture, for many texts speak of the word of God as life, light, saving power, and the like (Psalm 119: 109, John 5:39, 6:63, 17:20; Romans 1: 16, 10:18; Hebrews 4:12; 1 Peter 1:23; 2 Peter 1:19). Moreover, Article V of the Augsburg Confession clearly teaches that the word and sacraments are truly instruments through which the Spirit is “given and faith created.” From this truth Gerhard concludes that the word by virtue of divine order has an inner power to convert, The operative principle here is that every effect must come from a power that produces the effect (“actug gecundeg praegupponet pnmum, operatio vertutem”). The many metaphors in Scripture which speak of the efficacy of the word point in the same direction. There are, for example, the metaphors of the seed (Luke 8:11), of the fire (Luke 24:32; cf. Jeremiah 20:9), of the rain and snow (Isaiah 5:10), and of the light (Psalm 119: 105; 2 Peter 1:19).
 Bengt Hägglund, “The Theology of the Word in John Gerhard,” Concordia Theological Quarterly, vol. 46, no. 2-3 (April-July 1982), 209-217: 214.