“For the accustomed security of Quraysh, their security during winter and summer journeys, let them worship the Lord of this House.”
Al-Tabari and Ibn Kathir read verses 1 and 2 as one grammatical unit leading into verse 3: the security of the caravans is presented as the reason worship is owed. The winter journey went south to Yemen, the summer journey north to Syria, and both depended on Quraysh's unmolested reputation as guardians of the Kaaba.