Vermigli was primarily a teacher of scripture rather than a systematic theologian, but his lasting influence is mostly associated with his doctrine of the Eucharist. This can be explained by the close relationship he saw between exegesis of scripture and theological reflection. Vermigli's method of biblical commentary, similar to that of Martin Bucer, was to include extended discussions of doctrinal topics treated by the biblical texts. Like other Protestants, he believed scripture alone held supreme authority in establishing truth. Nevertheless, he was familiar with the church fathers to a higher degree than many of his contemporaries, and he constantly referred to them. He saw value in the fathers because they had discovered insights into the scriptures that he might not have found, and because many of his Catholic opponents placed great weight on arguments from patristic authority. Often, though, he used the fathers as support for interpretations he had already reached on his own and was not concerned when his interpretation had no patristic precedent.