Original sentence: The first item of the introduction argues that the currently existing translations of the Gospels were imperfect and were effectively unintelligible without proper relation to scholarly research about the culture and the customs of the peoples of the Middle-East
Edited sentence: The first item of the introduction argues that the currently existing translations of the Gospels were imperfect and were effectively unintelligible without proper relation to scholarly research about the culture and the customs of the peoples of the Middle-East (a rather advanced teaching for his time)