Before Dr. Johnston was a believer he doubted the accuracy of Scripture translations, and therefore the integrity of the Bible. After coming to faith he decided that the only way to find out whether the translations were reliable was to learn the original languages. After majoring in the classics at the University of Texas, he came to Dallas Seminary and discovered that teaching was his passion. Prior to joining the full-time faculty at Dallas Seminary, he taught Greek at The Criswell College and as an adjunct teacher at Dallas Seminary. His research interests are in Greek grammar, syntax, and Septuagint studies.