AKA Justin the Philosopher
He was an early Christian apologist and philosopher. His most well-known text is First Apology. He was martyred along with some of his students.
(Origin of the Bible handout by my small group leader, February 8, 2023. Summarized from Wikipedia. Page 4-5.)
One of his pupils was Tatian. (The Origin of the Bible: Newly Updated by F. F. Bruce, J. I. Packer, Philip W. Comfort, and Carl F. H. Henry, 2020. The Canon of the New Testament by Milton C. Fisher, Page 72.)
When Justin Martyr described worship services in the mid second century, he put apostolic writings on par with those of the Old Testament prophets, since the same voice spoke through them. He also was free in his use of "it is written" with quotations from New Testament Scriptures.
(The Origin of the Bible: Newly Updated by F. F. Bruce, J. I. Packer, Philip W. Comfort, and Carl F. H. Henry, 2020. The Canon of the New Testament by Milton C. Fisher, 71-72.)