Because they accustomed security in their journeys; to Yemen in winter and to Al-Sham in summer, every year for trading. These trips were their support in living in Mekkah and looking after the House (Ka’bah) which was represented their pride and glory.

If Allah (swt) was to leave Abraha to destroy the House, Quraish would have fallen, as such because the high rank of Quraish among the tribes and nations was because of the Holy House that Allah (swt) had protected, since the tribes have used to gather at. Hence, the relation between the two Surahs is clear; Allah (swt) made the elephant companions like eaten straw for the accustomed security of Quraish.