Bukhari

Hadith Commentary:
Yajuj and Majuj are two disbelieving nations from the descendants of Yafith, son of Nuh (Noah), among whose progeny are also the Russians and the Turks. Near the Day of Judgment, they will take control over the entire world and cause great chaos.
The complete mention of this will come under the signs of the Day of Judgment.
Imam Bukhari rahimahullah has brought this hadith here because, in its other narration, there appears to be a contradiction, but in reality, there is no contradiction. This is because the Day of Judgment will be established many days after the emergence and destruction of Yajuj and Majuj. Therefore, during the time of Yajuj and Majuj, people will continue to perform Hajj and Umrah.
After that, as the Day of Judgment draws nearer, disbelief will spread among the people, and Hajj and Umrah will be suspended.
The narration of Aban has been connected (mawsul) by Imam Ahmad rahimahullah, and the narration of Imran has been connected by Abu Ya‘la and Ibn Khuzaymah.
Hasan al-Basri rahimahullah said:
“La yazalu al-nasu ‘ala al-din ma hajjul-bayta wa istaqbalul-qiblah.”
(Fath)
That is, the Muslims will remain firm upon their religion as long as they perform Hajj to the Ka‘bah and face it in their prayers.

Hadith Commentary:
(1)
There appears to be a contradiction between these two narrations reported by Imam Bukhari rahimahullah, because the meaning of the first hadith is that even after the appearance of the signs of the Hour, the pilgrimage (Hajj) and lesser pilgrimage (Umrah) to the House of Allah (Baytullah) will continue, since the emergence of Gog and Magog (Ya’juj wa Ma’juj) is among the signs of the Hour. However, the implication of the second narration is that after the signs of the Hour, Hajj will be discontinued. Imam Bukhari rahimahullah has given preference to the first narration and considered the second as less preferred, because the narrators of the first hadith are more numerous than those of the second hadith.

(2)
This apparent contradiction can also be resolved in this way: after the emergence of Gog and Magog (Ya’juj wa Ma’juj), Hajj and Umrah will continue, but then, near the Hour, disbelief (kufr) will spread among the people, and thus Hajj and Umrah will also be discontinued. Hasan al-Basri rahimahullah said that Muslims will remain steadfast upon their religion as long as they continue to perform Hajj to the House of Allah and face it in prayer. (Fath al-Bari: 3/574)

(3)
The corroboration (mutaba‘at) of Aban and Imran has been mentioned by Imam Ahmad in his Musnad. (Musnad Ahmad: 3/27)