1 Timothy 4:9

The "trustworthy statement" Paul referred to here seems to have been what he had just said (1 Timothy 4:8). Several schools of philosophy in Paul’s day denigrated the excessive physical conditioning that many Greek young men practiced. [Note: Kelly, p. 100.] They believed the development of the inner man was more important. So perhaps this "trustworthy statement" was one that they had popularized. Paul agreed with this viewpoint whatever its source may have been.