3 When, in 1933, We consented, Venerable Brethren, to open negotiations for a concordat, which the Reich Government proposed on the basis of a scheme of several years' standing; and when, to your unanimous satisfaction, We concluded the negotiations by a solemn treaty, We were prompted by the desire, as it behooved Us, to secure for Germany the freedom of the Church's beneficent mission and the salvation of the souls in her care, as well as by the sincere wish to render the German people a service essential for its peaceful development and prosperity. Hence, despite many and grave misgivings, We then decided not to withhold Our consent for We wished to spare the Faithful of Germany, as far as it was humanly possible, the trials and difficulties they would have had to face, given the circumstances, had the negotiations fallen through. It was by acts that We wished to make it plain, Christ's interests being Our sole object, that the pacific and maternal hand of the Church would be extended to anyone who did not actually refuse it.
Source: Mit Brennender Sorge (Vatican.va)