Al-Qa'nabi recited the verse up to "full of knowledge and wisdom".
Ibn Abbas said: Allah is Most Clement and Most Merciful to the believers. He loves concealment. The people had neither curtains nor curtained canopies in their houses. Sometimes a servant, a child or a female orphan of a man entered while the man was having sexual intercourse with his wife. So Allah commanded them to ask permission in those times of undress. Then Allah brought them curtains and all good things. But I did not see anyone following it after that.
Abu Dawud said: The tradition of 'Ubaid Allah and of 'Ata, weakens this tradition.
In-book : Book 43, Hadith 420
English translation : Book 42, Hadith 5173