Praise be to Allah, the Lord of the Worlds. May peace and blessings be upon His Messenger, his family and Companions!
I have read the story copied from the book entitled "Al-Tarikh" written by Ibn Jarir Al-Tabary (may Allah be merciful with him) regarding Amir Al-Mu'minin (Commander of the Believers) `Umar ibn Al-Khattab (may Allah be pleased with him) in which he said,
" I followed him until he entered a house, and then he entered a room. I took permission to enter and saluted. I was permitted entry. When I entered, I found him sitting on a mat and leaning on two pillows made of leather and stuffed with palm fibers. He gave me one of them to sit on. I saw a hall in which there was a curtain. He said, "O, Um Kulthum! Bring us lunch." She brought him bread, oil and salt. He said, "O, Um Kulthum! Are not you going to eat with us?" She said, "I hear the voice of a man with you." He said, "Yes and I do not think he is one of the residents of the country." She said, "If you want me to sit with men, you would have bought me clothes like those bought by Ibn Ja`far to his wife, Al-Zubayr to his wife, or Talhah to his wife." He said, "Is not it enough for you to be said that Um Kulthum bint Ali ibn Abu Talib and the wife of Amir Al-Mu'minin `Umar?" He said, "Come on, eat. If she was satisfied, she would have brought you better food than this."
As for Riwayah, it was narrated by a group of weak narrators. Some of them are accused of being liars. The source of this tale who narrated this from `Umar, is an unknown person. Thus, it is false according to Riwayah.
As for Dirayah, there are a number of issues:
First, it is contradictory to what is known about `Umar (may Allah be pleased with him), his strictness in Hijab (veil), his extreme jealousy and his care that the Prophet's wives wear Hijab until the Ayah (Qur'anic verse) was revealed.
Second, it is contradictory to the rulings of Islam that were known to `Umar or other scholar. The Qur'an and Sunnah (whatever is reported from the Prophet) prove the obligation of wearing Hijab and the prohibition of free intermixing (of men and women) in a way that causes Fitnah (temptation).
Third, its text is absolutely rejected by anyone who contemplates it. In any case, this tale about `Umar is undoubtedly fabricated, whether to slander him, call for the free intermixing of men and women, or for other evil purposes. May Allah grant us safety!
Sheikh Abu Turab Al-Zhahiri, Sheikh Muhammad Ahmad Hisany and Dr. Hashim Bakr Habashi did well in their reply to this tale, clarifying its fabrication, and making it clear that such a tale cannot be attributed to Amir Al-Mu'minin `Umar ibn Al-Khattab (may Allah be pleased with him). May Allah reward them well, double their reward, grant us and them more knowledge and success, and make us and them of the supporters of Al-Haqq (the Truth).
I wrote this short speech to participate in revealing the truth and rejecting the falsehood to ascertain readers of the falsity of this tale, which is so dubious and unreliable for the aforesaid reasons. May Allah guide us all to the Straight Path, and protect us and all brothers from the evil souls and bad deeds! He is All-Hearing. May Allah's Peace be upon Prophet Muhammad!