To what extent the Gospel writers possessed the first of these qualifications--that is, power of observation and strength of memory--we are not informed by either history or tradition. But we are certainly justified in assuming to be true what the law actually presumes: that they were at least men of sound mind and average intelligence. This presumption, it may be remarked, continues to exist in favor of the witness until an objector appears who proves the contrary by competent and satisfactory evidence. It is not believed that this proof has ever been or can ever be successfully established in the case of the Evangelists. Aside from this legal presumption in their favor, there are certain considerations which lead us to believe that they were well qualified to speak truthfully and authoritatively about the matters relating to Gospel history. In the first place, the writings themselves indicate extraordinary mental vigor, as well as cultivated intelligence. The Gospels of Luke and John, moreover, reveal that the elegance of style and lofty imagery which are the invariable characteristics of intellectual depth and culture. The "ignorant fishermen" idea is certainly not applicable to the Gospel writers. If they were ever very ignorant, at the time of the composition of the Evangelical writings they had outgrown the affliction. The fact that the Gospels were written in Greek by Hebrews indicates that they were not entirely illiterate. Again, the occupations of two of them are very suggestive. Matthew was a collector at the seat of customs,[5] and Luke was a physician.[6] Both these callings required more than ordinary knowledge of men, as well as accurate powers of observation, discrimination, and analysis.