Both the Roman Catholic Church and the Eastern Orthodox Church contend that they are still in harmony with the teachings and practices Jesus gave the Apostles, and that Jesus' promise has been fulfilled: "On this rock I will build my church, and the gates of Hell shall not prevail against it." And elsewhere, "I will be with you until the end of the age." Also, "The Father ... will give you another Advocate to be with you always" and the passages of St. Paul describing the church as Christ's body and as the "pillar and bulwark of the truth" (1 Tim 3:15). They point to their claim of apostolic succession as evidence that they are maintaining authentic orthodox Christian teachings. They see claims of a complete apostasy (as opposed to a widespread revolt) as a denial of the promise that Jesus made (as recorded in scripture) to be with his Church "until the end of time". They also claim that their ecclesiastical structure (e.g. the Biblical practice of having bishops) and liturgical practices have their essential roots in the teachings and practices of the Apostles and early Christian community, and are not the result of radical changes introduced by either the imperial government or wave of pagan converts in the 4th century. They hold that elements of modern orthodox teachings can be traced back to the tradition of those known as the Ante-Nicene Fathers whose writings have some information about the sacraments, organizational structure, and general Christian lifestyle.