Semitic languages
The similarity of the Hebrew, Arabic and Aramaic languages was accepted by Jewish and Islamic scholars since medieval times. The languages were familiar to Western European scholars due to historical contact with neighbouring Near Eastern countries and through Biblical studies, and a comparative analysis of Hebrew, Arabic, and Aramaic was published in Latin in 1538 by Guillaume Postel. Almost two centuries later, Hiob Ludolf described the similarities between these three languages and the Ethiopian Semitic languages. However, neither scholar named this grouping as "Semitic".
Sacred language
However, Classical Arabic is not itself sacred, and holds no inherent spiritual significance. This is unlike, for example, the significance of Biblical Hebrew in Judaism, Sanskrit in Hinduism, or Avestan in Zoroastrianism. Though the Qur'an was revealed to Muhammad in Arabic, other prophets received revelation in their own languages - e.g., Moses was revealed the Torah in Hebrew, and Jesus was revealed the Injil in Aramaic. These revelations were no less divine than the Qur'an; their texts have only become less divine, as their original message was corrupted over generations. The Arabic used in Muslim worship was also the same language used in day-to-day life by Arabs at the time, and the fact that the Qur'an was revealed to humans in Arabic does not make the Arabic language itself more sacred than any other. Sermons are delivered in local vernacular.