Final answer:
The Arabs and Swahili have in common a majority belief in Islam, which became the foundation for trade and cultural interactions along the Swahili coast. A syncretic form of Islam with local African traditions emerged among the Swahili civilization, strengthening the link between Arab and Bantu cultures.
Step-by-step explanation:
Arabs and Swahili peoples share a commonality in their majority belief in Islam. The Bantu peoples, residing on the East African coast, converted to Islam over centuries, interacting closely with Arab and Persian merchants. The Swahili civilization that developed was significantly shaped by this Islamic influence, though it retained aspects of local African traditions, creating a unique syncretic form of Islam. The Swahili language, an important cultural element, emerged as a Bantu language infused with Arabic words, further cementing the strong ties between Arab culture and the Bantu-speaking peoples of the East African coast.
Moreover, by the end of the fourteenth century, Islam had spread throughout North Africa to eastern Persia, and the Muslim community's diversity of languages and cultures contributed to the religious unity across regions. The Swahili coast grew as an important commercial hub due to this socio-cultural exchange and became recognized for its Islamic faith melded with local customs.