136 No genuine cure can be furnished for this lamentable ruin of souls, which, so long as it continues, will frustrate all efforts to regenerate society, unless men return openly and sincerely to the teaching of the Gospel, to the precepts of Him Who alone has the words of everlasting life, words which will never pass away, even if Heaven and earth will pass away. All experts in social problems are seeking eagerly a structure so fashioned in accordance with the norms of reason that it can lead economic life back to sound and right order. But this order, which We Ourselves ardently long for and with all Our efforts promote, will be wholly defective and incomplete unless all the activities of men harmoniously unite to imitate and attain, in so far as it lies within human strength, the marvelous unity of the Divine plan. We mean that perfect order which the Church with great force and power preaches and which right human reason itself demands, that all things be directed to God as the first and supreme end of all created activity, and that all created good under God be considered as mere instruments to be used only in so far as they conduce to the attainment of the supreme end. Nor is it to be thought that gainful occupations are thereby belittled or judged less consonant with human dignity; on the contrary, we are taught to recognize in them with reverence the manifest will of the Divine Creator Who placed man upon the earth to work it and use it in a multitude of ways for his needs. Those who are engaged in producing goods, therefore, are not forbidden to increase their fortune in a just and lawful manner; for it is only fair that he who renders service to the community and makes it richer should also, through the increased wealth of the community, be made richer himself according to his position, provided that all these things be sought with due respect for the laws of God and without impairing the rights of others and that they be employed in accordance with faith and right reason. If these principles are observed by everyone, everywhere, and always, not only the production and acquisition of goods but also the use of wealth, which now is seen to be so often contrary to right order, will be brought back soon within the bounds of equity and just distribution. The sordid love of wealth, which is the shame and great sin of our age, will be opposed in actual fact by the gentle yet effective law of Christian moderation which commands man to seek first the Kingdom of God and His justice, with the assurance that, by virtue of God's kindness and unfailing promise, temporal goods also, in so far as he has need of them, shall be given him besides.
Source: Quadragesimo Anno (Vatican.va)