Why are Arabs called messengers of communication between eastern and western civilizations?

In the Middle Ages, Arabs were the leaders of world trade. The trade route revolves around the Middle East, with the sea leading to Korea and Japan in the east, the Pyrenees Peninsula in the west, and the Silk Road on land, which is connected with both eastern and western civilizations. The long-distance trade between the Far East and Western Europe depends on the contact of Arabs. This huge trade network has also become a channel for exchanges between eastern and western civilizations: through the contact of Arab businessmen, the inventions and creations of East Asia first flowed into the Middle East and then into Western Europe; Western European goods, weapons inventions and various religious beliefs also entered China from the Middle East.