Surah 106. Quraish, Ayah 2

I.e., the two annual trade caravans - to the Yemen in winter and to Syria in summer - on which the prosperity of Mecca depended.

See last note, especially section (2). On account of their trade journeys to the warmth of Yaman in the winter and the cooler regions of Syria and the north in the summer, the Quraish became practised travellers and merchants, acquired much knowledge of the world and perfected their language as a polished medium of literary expression.