It is based on an actual teaching of the apostle Paul and is part of the promise of Salvation from the Judgment that is coming to this world and upon all of you foolish unbelievers. (religion.blogs.cnn.com)
The Didache which is also called Teachings of the Apostles is one of the oldest surviving documents of canonical teaching we have. (relevantmagazine.com)
Thus Clement regarded the Didache or Teaching of the Apostles as scriptural; both he and Origen viewed the author of I Clement as the Clement mentioned by Paul in Philippians 4:3 and the author of the Shepherd as the Hernias of Romans 16:4. (religion-online.org)