According to the commentators of the Qur’an, the women of Medina in the pre-Islamic era used to put their khumur over the head with the two ends tucked behind and tied at the back of the neck, in the process exposing their ears and neck. By saying that, “place the khumur over the bosoms,” Almighty Allah ordered the women to let the two ends of their headgear extend onto their bosoms so that they conceal their ears, the neck, and the upper part of the bosom also.3
This is confirmed by the way the Muslim women of the Prophet’s era understood this commandment of Almighty Allah. The Sunni sources quote Ummu ’l-mu’minin ‘A’isha, the Prophet’s wife, as follows: “I have not seen women better than those of al-Ansar (the inhabitants of Medina): when this verse was revealed, all of them got hold of their aprons, tore them apart, and used them to cover their heads...”4
The meaning of khimar and the context in which the verse was revealed clearly talks about concealing the head and then using the loose ends of the scarf to conceal the neck and the bosom. It is absurd to believe that the Qur’an would use the word khimar (which, by definition, means a cloth that covers the head) only to conceal the bosom with the exclusion of the head! It would be like saying to put on your shirt only around the belly or the waist without covering the chest!
Finally the verse goes on to give the list of the mahram – male family members in whose presence the hijab is not required, such as the husband, the father, the father-in-law, the son(s), and others.