Carl Müller is also at pains to show that it was Melanchthon who imbued the first generation of theologians—for whose formation he, rather than Luther, was responsible—with the idea of a Church which should be the guardian of that “pure doctrine” to be enshrined in formularies of faith. According to Müller it can never be sufficiently emphasised that the common idea is all wrong, and that “to Luther himself the Church never meant a congregation united by outward bonds or represented by a hierarchy or any other legal constitution, rule or elaborate creed, but nothing more than a union founded on the Gospel and its confession”; Luther, according to him, remained “on the whole” true to his ideal.[1163] How far the words “on the whole” are correct, will be seen when we come to discuss Luther’s changes of views.[1164] Melanchthon betrays a certain indecision in his answer to the weighty question: Which faith is essential for salvation? At one time he takes this faith, according to the common Lutheran view, as trust in the mercy of God in Christ, at another, as assent to the whole revealed Word of God. Of his Disputations, which are the best witnesses we have to his attitude, the editor says aptly: “He alternates between two definitions of faith which he seems to consider of equal value, though to-day the difference between them cannot fail to strike one. He wavers, and yet he does so quite unconsciously.”[1165] The same editor also states that all attempts hitherto made to explain this phenomenon leave something to be desired. He himself makes no such attempt. The true explanation, however, is not far to seek.