The question stated in the title refers primarily to the awareness that there were indeed inspired writings, such as the First Letter to the Corinthians (cf. 1Cor 5:9), which is not even preserved in the oldest codes. To resolve this question you first need to provide answers to the following questions: What is the inspiration? How was the canon of the inspired books shaped? What is the Gospel and what is the difference between canonical and apocryphal gospels? There are important elements related to the inspiration that are meaningful to the discussed issues. Firstly, the revelation ended with the death of the last apostle. Secondly, the early Church became the norm of faith for the future generations. Thirdly, writing (especially letters) were written for a specific purpose. In the fourth place, the authorship of the Bible does not affect their inspired style. In the fifth place, the inspired books have a certain style and language that govern the rights of the times in which they arose. Taking into account all these elements we cannot deny the theoretical possibility of the discovery of the „disappeared” inspired writings, but an integral understanding of the revelation allows us to think of their possible finding that does not change in any way the content of revelation. In relation to the canon of the sacred books it seems to be a particularly important fact recalled by Benedict XVI in the Apostolic Exhortation Verbum Domini of inspiration, which was and is a deposit which the Church has received from God. This argument allows us to conclude that the Church, as the primary custodian of inspiration, provides comprehensive nature of revelation. Even if there was discovered some hitherto unknown letter, with all certainty inspired, it would not add anything new to the revelation that God had already revealed before. In relation to the gospel, we notice that there is only one, unchanged Gospel, and its content is the cross and resurrection of Christ (1Cor 15:3-5), that is the coming of the kingdom of God (Mark 1:14-15). In the canon of the New Testament books of the Bible there are four books, which we can define the literary genre of the concept of the gospel (Matthew, Mark, Luke and John). There are not, however, four separate versions of the message of the Good News but rather a slightly different view of the same reality of coming of the kingdom of God and its fulfillment in the cross of Christ and His resurrection. Such content cannot be found in the apocryphal gospels. There is therefore no basis for concern that it could come to the discovery of some sort of a letter that would change the way of looking at the reality of Jesus Christ and His art of saving.