Heinrich Bullinger, Zwingli's successor as chief pastor of Zurich, wrote the Second Helvetic Confession in 1562 as a private statement of his own faith, intended to be opened after his death and attached to his will rather than published for the churches. Frederick III, Elector Palatine, changed its course. Attacked at the Diet of Augsburg in 1566 by Lutheran princes who held that his sponsorship of the Heidelberg Catechism amounted to harbouring Calvinist heresy, Frederick asked Bullinger for a confession he could set before them, and Bullinger sent the testament he already had. It was revised a little, translated, and published within the year.
Its thirty chapters are unusually expansive for a confession. It opens with a full treatment of Scripture as the Word of God, interpreted out of itself and by the rule of love and of faith, and continues through God, providence, the fall, the law, the gospel, Christ, the church, the ministry, the sacraments, festivals, fasting, catechising, the burial of the dead and the state, a range closer to a theological handbook than to a compact statement of contested points.
Its most quoted sentence, that the preaching of the Word of God is itself the Word of God, gives the whole document its centre: the Reformed conviction that a rightly preached sermon carries the authority of the text it expounds rather than merely commenting on it. Bullinger had spent forty years in the Zurich pulpit when he wrote it, and the confession reads as the work of a preacher rather than of a committee.