Catholic Encyclopedia (1913)/Gospel of Saint Luke (Biblical Commission)
Luke, Saint, Gospel of—The following answers to questions about this Gospel, and that of St. Mark, were issued, June 26, 1913, by the Biblical Commission (q.v.). That Mark, the disciple and interpreter of Peter, and Luke, a doctor, the assistant and companion of Paul, are really the authors of the Gospels respectively attributed to them is clear from Tradition, the testimonies of the Fathers and ecclesiastical writers, by quotations in their writings, the usage of early heretics, by versions of the New Testament in the most ancient and common manuscripts, and by intrinsic evidence in the text of the Sacred Books. The reasons adduced by some critics against Mark's authorship of the last twelve versicles of his Gospel (xvi, 9-20) do not prove that these versicles are not inspired or canonical, or that Mark is not their author. It is not lawful to doubt of the inspiration and canonicity of the narratives of Luke on the infancy of Christ (i-ii), on the apparition of the Angel and of the bloody sweat (xxii, 43-44); nor can it be proved that these narratives do not belong to the genuine Gospel of Luke.
The very few exceptional documents attributing the Magnificat to Elizabeth and not to the Blessed Virgin should not prevail against the testimony of nearly all the codices of the original Greek and of the versions, the interpretation required by the context, the mind of the Virgin herself, and the constant tradition of the Church.
It is according to most ancient and constant tradition that after Matthew, Mark wrote his Gospel second and Luke third; though it may be held that the second and third Gospels were composed before the Greek version of the first Gospel. It is not lawful to put the date of the Gospels of Mark and Luke as late as the destruction of Jerusalem or after the siege had begun. The Gospel of Luke preceded his Acts of the Apostles, and was therefore composed before the end of the Roman imprisonment, when the Acts was finished (Acts, xxviii, 30-31). In view of Tradition and of internal evidence it cannot be doubted that Mark wrote according to the preaching of Peter, and Luke according to that of Paul, and that both had at their disposal other trustworthy sources, oral or written.
Acta Apostolicæ Sedis (30 June, 1913)