Praise be to Allah.
There is a mistake in the quoting of the hadeeth in question. The hadeeth was narrated by al-Bukhaari (may Allaah have mercy on him) in his Saheeh, in Kitaab Fadaa’il al-Madeenah (the Book of the Virtues of Madeenah, 1879) and in Kitaab al-Fitan (The Book of Tribulations, 7125), from the hadeeth of Abu Bakrah (may Allaah be pleasaed with him), who narrated that the Prophet (peace and blessings of Allaah be upon him) said:
“The feeling of terror of the Dajaal will not enter Madeenah. At that time it will have seven gates, at each of which will be two angels.”
Ibn Hajar al-‘Asqallaani (may Allaah have mercy on him) said in his footnote on this hadeeth, with regard to the phrase “At that time it will have seven gates”:
‘Iyaad said: this supports the idea that what is meant here by gates is paths, as in the hadeeth of Abu Hurayrah. It was reported in al-Saheeh from Abu Hurayrah that the Messenger of Allaah (peace and blessings of Allaah be upon him) said:
On the pathways of Madeenah there are angels, and neither the plague nor the Dajjaal will enter it.
Al-Haafiz said in Al-Fath (4/96): “Al-Anqaab (pathways) is the plural of Naqab… Ibn Wahb said: what is meant by this is entrances, or it was said that it means gates. The original meaning of Naqab was a path between two mountains. It was said that al-anqaab were the routes which people followed, as in the aayah (interpretation of the meaning):
“… they ran for a refuge (naqqabu) in the land” [Qaaf 50:36]
This is all that al-Haafiz said in his commentary on the gates. There is still room for ijtihaad on this issue, and it could mean for example:
That Madeenah will have gates in the future when the Dajjaal comes, even though it does not have gates at the present time.
That what is meant by gates is the main entrances to the city, even if they do not take the form of gates.
That the angels who are appointed to guard it are covering seven points, at each of which there are two angels, and the points were described as gates – which is acceptable in Arabic.
And Allaah knows best.