18 Not with the conquest of material space does one approach to God, separation from Whom is death, conversion to Whom is life, to be established in Whom is glory; but under the guidance of Christ with the fullness of sincere faith, with unsullied conscience and upright will, with holy works, with the achievement and the employment of that genuine liberty whose sacred rules are found proclaimed in the Gospel. If, instead, the Commandments of God are spurned, not only is it impossible to attain that happiness which has place beyond the brief span of time which is allotted to earthly existence, but the very basis upon which rests true civilization is shaken and naught is to be expected but ruins over which belated tears must be shed. How, in fact, can the public weal and the glory of civilized life have any guarantee of stability when right is subverted and virtue despised and decried? Is not God the Source and the Giver of law? Is He not the inspiration and the reward of virtue with none like unto Him among lawgivers (Cf. Job XXXVI:22)? This, according to the admission of all reasonable men, is everywhere the bitter and prolific root of evils: the refusal to recognize the Divine Majesty, the neglect of the moral law, the origin of which is from Heaven, or that regrettable inconstancy which makes its victims waver between the lawful and the forbidden, between justice and iniquity.
Source: Sertum Laetitiae (Vatican.va)