Neither the Dajjal nor the plague will enter Madinah

Sayyiduna Jabir bin Abdullah (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) looked out over the stony ground, and we were with him. He said: "Madinah is an excellent land. When the Dajjal emerges, there will be an angel at every road into Madinah, and the Dajjal will not be able to enter it. When that time comes, Madinah will be shaken by three earthquakes, and every hypocrite man and hypocrite woman will go out and go over to the Dajjal, and most of those who go to him will be women. That will be the Day of Deliverance, when Madinah will expel its impurity just as a furnace removes the impurity (that is, the rust) of iron. With the Dajjal there will be seventy thousand Jews, each of whom will have a green shawl and an adorned sword. He (that is, the Dajjal) will pitch his tent at the place where the streams' water gathers." Then the Prophet (peace and blessings be upon him) said: "No trial has ever passed, and none will occur until the Hour is established, greater than the trial of the Dajjal. Every prophet urged his nation to beware of it, and I am about to tell you something that no prophet told his nation." A request was made to him about this, and he placed his blessed hand over his eye and then said: "Indeed, Allah Almighty is not one-eyed" (the Prophet (peace and blessings be upon him) meant that the Dajjal will be one-eyed). (Allamah al-Haythami says:) I say: Part of it is reported in the "Sahih": "Madinah is like a furnace, which removes impurity and makes the pure shine."
Imam Ahmad recorded it.

Imam al-Tabarani also recorded this narration in al-Mu'jam al-Awsat, and the words of his narration are: The narrator says: The Prophet (peace and blessings be upon him) said: "O people of Madinah, remember the Day of Deliverance!" The people asked: "What is meant by the Day of Deliverance?" The Prophet (peace and blessings be upon him) said: "The Dajjal will come and camp at a place called 'Dhubab'. At that time every polytheist man and polytheist woman, disbeliever man and disbeliever woman, hypocrite man and hypocrite woman, and sinful man and sinful woman in Madinah will go out and go over to him, and only the Muslims will remain. That is the Day of Purification" (and the rest of the hadith).
The narrators of Imam Ahmad are the narrators of the Sahih.

Sayyiduna Mihjan bin al-Adra' (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him), while addressing the people, said: "The Day of Purification! What is the Day of Purification? The Day of Purification! What is the Day of Purification? The Day of Purification! What is the Day of Purification?" He said this three times. It was asked: "What is the Day of Purification?" The Prophet (peace and blessings be upon him) said: "The Dajjal will come. He will climb Mount Uhud and say to his companions: 'Do you see this white palace? This is the mosque of Ahmad.' Then he will come to Madinah and find at every road into Madinah an angel with a drawn sword. Then he will come to the salt marsh of al-Juruf and pitch his canopy. Then Madinah will be shaken by three earthquakes, and no hypocrite man or hypocrite woman, nor any sinful man or sinful woman, will remain without going out and going over to him. That will be the Day of Deliverance (or of Purification)."
Imam Ahmad recorded it, and its narrators are the narrators of the Sahih.

In a narration which Imam Ahmad also recorded from Raja', he narrates: Sayyiduna Buraydah (may Allah be pleased with him) was at the door of the mosque. Sayyiduna Mihjan (may Allah be pleased with him) passed by him, while Sayyiduna Sakbah (may Allah be pleased with him) was praying at that time. Sayyiduna Buraydah (may Allah be pleased with him), who had a playful temperament, said to Sayyiduna Mihjan (may Allah be pleased with him): "Do you not pray the way this man is praying (with humility and devotion)?" Sayyiduna Mihjan (may Allah be pleased with him) said: Once the Prophet (peace and blessings be upon him) took hold of my hand and turned towards Madinah, and said: "Woe to its mother! It is a town whose inhabitants will abandon it while it is at its best. The Dajjal will come to it and will find at each of its gates an angel with his wing drawn (like a sword), and he will not be able to enter it." The narrator says: Then the Prophet (peace and blessings be upon him) came down while holding my hand, and he entered the mosque. A man was praying, and he asked me: "Who is this?" I went to him and then praised him. The Prophet (peace and blessings be upon him) said: "Be quiet! Do not let him hear this, or you will destroy him." The narrator says: The Prophet (peace and blessings be upon him) came to the apartment of one of his wives, released his hand from mine and said: "The best of your religion is that which is easiest. The best of your religion is that which is easiest."
Imam Ahmad recorded it, and its narrators are the narrators of the Sahih, except for the narrator named Raja', whose case is different; Ibn Hibban declared him thiqah (trustworthy).

Abu Abdullah al-Qarraz narrates that he heard Sayyiduna Sa'd bin Malik (may Allah be pleased with him) and Sayyiduna Abu Hurayrah (may Allah be pleased with him) state: The Prophet (peace and blessings be upon him) said: "O Allah! Place blessing for the people of Madinah in their city, place blessing for them in their sa', and place blessing for them in their mudd. O Allah! Sayyiduna Ibrahim (peace be upon him) was Your servant and Your Khalil (intimate friend), and I am Your servant and Your Messenger. Sayyiduna Ibrahim (peace be upon him) asked You on behalf of the people of Makkah, and I ask You on behalf of the people of Madinah the like of what Sayyiduna Ibrahim (peace be upon him) asked for Makkah, and as much again along with it. Indeed, Madinah is encircled by angels; at every road into it there are two angels guarding it. Neither the plague nor the Dajjal can enter it. Whoever intends evil towards it, Allah Almighty will dissolve him (in the fire of Hell) just as salt dissolves in water."
(Allamah al-Haythami says:) I say: Part of it is reported in the "Sahih".
Imam Ahmad recorded it, and its narrators are the narrators of the Sahih.

Sayyiduna Abu Hurayrah (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) said: "Madinah and Makkah are surrounded by angels; at every road into them there is an angel. Neither the Dajjal nor the plague will enter them."
Imam Ahmad recorded it, and its narrators are thiqat (trustworthy).

A paternal cousin of Sayyiduna Usamah bin Zayd (may Allah be pleased with him), whose name was Iyad and whose wife was the daughter of Sayyiduna Usamah (may Allah be pleased with him), narrates: A man was mentioned before the Prophet (peace and blessings be upon him) who had set out from some fertile region. When he reached a place on the road near Madinah, an epidemic struck him, and this alarmed the people. The narrator says: The Prophet (peace and blessings be upon him) said: "I hope that it will not come upon us through its passes" - the Prophet (peace and blessings be upon him) meant (the passes of) Madinah.
Imam Ahmad recorded it in this way as a "mursal" narration; his son Abdullah also narrated it, and Imam al-Tabarani recorded it in al-Mu'jam al-Kabir with a connected chain; and its narrators are thiqat (trustworthy).

Sayyiduna Tamim al-Dari (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) said: "Indeed, Madinah is pure (Taybah). On every one of its paths an angel stands with his sword drawn; the Dajjal will never enter it."
Imam al-Tabarani recorded this in al-Mu'jam al-Kabir as a narration of Umar bin Yazid from his grandfather, and I do not know either of them.

Abdullah bin Shaqiq relates: I was walking with Sayyiduna Imran bin Husayn (may Allah be pleased with him). We reached the mosque of Basrah, and there Sayyiduna Buraydah (may Allah be pleased with him) was sitting, while Sayyiduna Sakbah (may Allah be pleased with him), who belonged to the tribe of Aslam and was a Companion of the Prophet (peace and blessings be upon him), was standing offering the forenoon (Duha) prayer. Sayyiduna Buraydah (may Allah be pleased with him) said: "O Imran, are you not able to pray the way Sakbah prays?" He said this, meaning him by it. Sayyiduna Imran (may Allah be pleased with him) remained silent, and then the two of them went on. Then Sayyiduna Imran (may Allah be pleased with him) said: I was walking with the Prophet (peace and blessings be upon him) when Mount Uhud came before us, and we climbed it. The Prophet (peace and blessings be upon him) looked out over Madinah and said: "Woe to its mother! It is a town which its inhabitants will leave when it is at its very best. The Dajjal will come to it but will not be able to enter it; he will find on every one of its paths an angel standing with his sword drawn." The narrator says: Then we came down from the mountain and came to the mosque, and there a man was praying. He asked: "Who is this?" I said: "This is so-and-so," and I mentioned his affairs and praised him. The Prophet (peace and blessings be upon him) said: "Do not let him hear (this praise), or you will break his back." Then the Prophet (peace and blessings be upon him) raised my hands and said: "The best of your religion is the easiest of it."
Imam al-Tabarani recorded this in al-Mu'jam al-Kabir, and its narrators are the narrators of the Sahih.

Sayyiduna Mihjan bin al-Adra' (may Allah be pleased with him) relates: The Prophet (peace and blessings be upon him) sent me on some errand. Then he came across me while I was going out along the road of Madinah. He took my hand and we walked on until we climbed Mount Uhud. The Prophet (peace and blessings be upon him) turned towards Madinah and said: "Woe to its mother! It is a town which its inhabitants will leave in a state when its fruits are fully ripe." I said: "O Messenger of Allah! Who will eat its fruit?" The Prophet (peace and blessings be upon him) said: "The birds and the wild beasts (will eat it). But the Dajjal will not be able to enter it; whenever he intends to enter it, an angel will come into his way and turn him back." Then the Prophet (peace and blessings be upon him) came back until, when we reached the door of the mosque, a man was praying there. The Prophet (peace and blessings be upon him) said: "He is reciting this with a sincere heart." I said: "O Messenger of Allah! This is so-and-so, who prays more than anyone in Madinah." The Prophet (peace and blessings be upon him) said: "Do not let him hear this, or you will destroy him." (Allamah al-Haythami says:) I say: Imam Abu Dawud recorded a part of this narration.
Imam al-Tabarani recorded this in al-Mu'jam al-Awsat, and its narrators are the narrators of the Sahih. A chain of this hadith has already passed before this, which Imam Ahmad narrated.