So I'm studying the Solid Declaration of the Formula of Concord and I'm on article II: "Free Will, or Human Power." The status of the controversy which was resolved by the Formula of Concord (formula for peace between the controversial theological points) concerns what power, if any, sinful human beings have to cooperate or participate with God's work of converting to faith in Christ. The following says it all:
In order to explain this controversy in a Christian way, according to the guidance of God's Word, and to decide it by His grace, our doctrine, faith, and confession are as follows:
In spiritual and divine things the unregenerate person's intellect, heart, and will are utterly unable, by his natural powers, to understand, believe, accept, think, will, begin, effect, do, work, or concur in working anything. They are entirely dead to what is good (Ephesians 2:5). They are corrupt. So in mankind's nature since the fall, before regeneration, there is not the least spark of spiritual power remaining or present. No person can prepare himself for God's grace or accept the grace God offers. A person is not capable of grace for and of himself. He cannot apply or accommodate himself to it. By his own powers he is not able to aid, do, work, or agree in working anything toward his conversion. He cannot do this fully, halfway, or even in part—not even in the smallest or most trivial part. He is sin's servant (John 8:34) and the devil's captive, by whom he is moved (Ephesians 2:2; 2 Timothy 2:26). Therefore, the natural free will according its perverted disposition and nature is strong and active only to do what is displeasing and contrary to God (Genesis 6:5).
In other words, there is nothing —absolutely nothing!— we can to bring ourselves to saving faith in Jesus Christ my Lord or even to prepare ourselves for grace. Nothing, nada, nichts, rien, niente! And so what a miracle of God's mercy that He uses His precious means of grace to call us to faith... that (despite all this) we are called by the Gospel, enlightened with His gifts, sanctified and kept in the true faith. Glory to God in the highest! Thanks be to God!
Source: Formula, Solid Declaration, II:6-7, "Concordia, the Lutheran Confessions: A Reader's Edition of the Book of Concord" (St. Louis: Concordia Publishing House, 2005), first edition, p. 551.