Verse 14of 17

Swearing to the Truthfulness of the Qur'an and the Failure of Those Who oppose itIbn `Abbas said, "Ar-raj` means rain." It has also been narrated from him that he said, "It means the clouds that contain rain." He also said,وَالسَّمَآءِ ذَاتِ الرَّجْعِ (By the sky (having rain clouds) which gives rain, again and again.) "This means that it rains and then it rains (again)." Qatadah said, "It returns the sustenance of the servants (creatures) every year.

Source: Tafsir Ibn Kathir — abridged excerpt