Further, Christianity although conceived as a religion for all mankind, was founded on a definite code and revelation. The primary statement was contained in the canonical books of the Old and New Testaments. These were for all men, universal in application and of irrefragable validity and truth. Here was some correspondence to the conception of the _jus gentium_ as representative of universal principles of justice and expediency, and therefore as equivalent to the _jus naturale_. There was something of logical necessity in the transference of this conception to the law of Christ. Says Gratian at the beginning of his _Decretum_: “It is _jus naturae_ which is contained in the Law and the Gospel, by which every one is commanded to do to another as he would be done by, and forbidden to inflict on him what he does not wish to happen to himself.” Since the Law and the Gospel represent the final law of life for all men, they are _par excellence_ the _jus naturae_, as well as _lex divina_. Gratian quotes from Augustine: “Divinum jus in scripturis divinis habemus, humanum in legibus regum.”[403] And then adds: “By its authority the _jus naturale_ prevails over custom and constitution. Whatever in customs or writings is contrary to the _jus naturale_ is to be held vain and invalid.” Again he says more explicitly: “Since therefore nothing is commanded by natural law other than what God wills to be, and nothing is forbidden except what God prohibits, and since nothing may be found in the canonical Scripture except what is in the divine laws, the laws will rest divinely in nature (_divine leges natura consistent_). It is evident, that whatever is proved to be contrary to the divine will or canonical Scripture, is likewise opposed to natural law. Wherefore whatever should give way before divine will or Scripture or the divine laws, over that ought the _jus naturale_ to prevail. Therefore whatever ecclesiastical or secular constitutions are contrary to natural law are to be shut out.”[404] The canon law is a vast sea. Its growth, its age-long agglomerate accretion, the systematization of its huge contents, have long been subjects for controversialists and scholars. Its sources were as multifarious as those of the Roman law. First the Scriptures and the early quasi-apostolic and pseudo-apostolic writings; then the traditions of primitive Christianity and also the writings of the Fathers; likewise ecclesiastical customs, long accepted and legitimate, and finally the two great written sources, the decretals or decisions of the popes and the decrees of councils. From patristic times collections were made of the last. These collections from a chronological gradually acquired a topical and more systemic arrangement, which the compilers followed more completely after the opening of the tenth century. The decisions of the popes also had been collected, and then were joined to conciliar compilations and arranged after the same topical plan.