External evidence

The scholarly debate about the authorship of this letter can be divided into two parts, external and internal evidence.  The external evidence for its authenticity, rests on the citations of this letter in other writings among the Apostolic Fathers of the late first and early second centuries.  Clement of Rome, who was the bishop of Rome from 88-99 CE, cited this letter.  Ignatius, the bishop of Antioch, (108 CE) also mentioned the letters of Peter.  Other early Christian writers mentioned 2 Peter, such as Aristides (134 CE), Polycarp (155 CE), and Justin (165 CE), Theophilus (183 CE), Clement of Alexandria (211 CE), and Origen (185–254 CE).  Thus, the Christian leaders who came after Peter in the late first and second century had no objection to Peter as the author of this letter.  How reliable is second hand evidence?