The word 'min' is for partitive meaning, and the intention is to lower the gaze from what is forbidden, and to restrict it to what is permissible. Al-Akhfash permitted that it may be an addition, but Sibawayh rejected it. If you say: How did it enter into lowering the gaze without preserving the private parts? I say: It indicates that the matter of looking is broader. Do you not see that it is permissible to look at the hair, chests, breasts, upper arms, calves, and feet of the non-mahram women? And similarly, for the slave girls who are displayed. As for the foreign woman, it is permissible to look at her face, hands, and feet in one of the narrations. As for the matter of the private parts, it is restricted. It is enough for you to distinguish that looking is permitted except for what is excluded, and sexual intercourse is prohibited except for what is excluded. It may be intended - while preserving them from leading to what is not permissible - to preserve them from being exposed. Ibn Zayd said: Everything in the Qur'an regarding preserving the private parts is about fornication, except for this, for it intended covering. Then He informed that He is All-Aware of their actions and conditions, and how they cast their glances? And how they act with their other senses and limbs? So upon them - since they know that - to be cautious and wary of Him in every movement and stillness.