Justin Martyr (c. 100 - c. 165) was one of the earliest of the Apologists, spokesmen who offered an apologia, a reasoned defense of Christianity (Acts Acts 22:1; 1Pe. 1Pe. 3:15). Justin studied philosophy prior to his conversion to Christ. In his Dialogue with Trypho he attempts to explain to a Jew named Trypho how Jesus Christ is the fulfillment of the prophecies of Messiah from the Jewish OT.1
1 Edwin M. Yamauchi, Justin Martyr: Defender of the Faith, in John D. Woodbridge, ed., Great Leaders of the Christian Church (Chicago, IL: Houghton Mifflin, 1993), 39-42.