There are multiple narrations that point to the return of Prophet Mohammed (PBUH & His Family) during the end times. Imam Ahmed Al-Hassan (From Him is Peace) revealed that Prophet Mohammed (PBUH & His Family) has indeed returned and that he reincarnated as the Twelfth Imam, Imam Mohammed ibn Al-Hassan Al-Askari (PBUH & His Family) the long-awaited Imam Mahdi.
In the Book of Monotheism Imam Ahmed Al-Hassan (From Him is Peace) says:
And His [The Exalted] saying: {Do they await but that Allah comes to them in shades of clouds and the angels [as well] and the matter is [then] decided And to Allah [all] matters are returned} [Surat Al-Baqarah 2:210]. So the one who comes in the shades of clouds is Muhammad (pbuh & his Family) in the World of Raja' (The world of Return) and with him shall be the People of his House (Ahlul Bayt) and some of the Prophets (pbut). And it is known that Muhammad is the one shaded with the clouds, and there were glad tidings given with this description in the Torah and The Gospels about the Messenger Muhammad and the Riser (Al-Qa'im) from the family of Muhammad composed of parts and being counted. He, The Exalted, said: {Say He is Allah The One/The Indivisible}, meaning that His Essence is Indivisible and not composed of parts for Him to have a hand and a leg, Allah is Exalted and Higher than what they associate. And [being] counted accompanies [being] composed of parts, and it is clear and obvious in its indication towards the Shirk of he whom confirms it, because it means plurality of the Absolute Divine. Allah is far Exalted and Higher than what they oppressor say.
– Book of Monotheism , Imam Ahmed Al-Hassan (From Him is Peace), English Translation p. 80
Abu Khalid Al-Kabili narrated from Ali ibn Al-Hussain (PBUH) regarding the verse “Verily, He Who has given you the Qur’an will surely bring you back at an appointed time." [Surah 28:85] he (PBUH) said: “Your Prophet (PBUH & His Family) shall return to you”.
– Bihar Al-Anwar, Al-Allamah Al-Majlisi, Vol. 53, p. 56; Mukhtasar Basa'ir Al-Darajat, Al-Hassan Ibn Sulayman Al-Hilli, p. 44
Abi Marwan narrated: I asked Aba Abdillah (PBUH) about the saying of Allah,“Verily, He Who has given you the Qur’anwill surely bring you back at an appointed time." [Surah 28:85] he (PBUH) said: “No, by Allah! The world does not end till the Messenger of Allah (PBUH & His Family) and Ali (PBUH) come together in Al-Thawiyya, they meet each other and build a mosque with 12,000 entrances in Al-Thawiyya, meaning a place in Al-Kufa.”
– Bihar Al-Anwar, Al-Allamah Al-Majlisi, Vol. 53, p. 113; Mukhtasar Basa'ir Al-Darajat, Al-Hassan Ibn Sulayman Al-Hilli, p. 210
Jabir ibn Yazid narrated that Aba Ja’far (PBUH) said about the saying of Allah the Almighty, "O you who covers himself [with a garment] Arise and warn." [Surah 74:1-2]: “He means by that Mohammed (PBUH & His Family) and his rise in the Raj’a (Return), he will warn in it. And His saying: “Surely, it is one of the greatest portents As a warner to humanity.” [Surah 74:35-36] Meaning Mohammed (PBUH & His Family), a warner to humanity, in the Raj’a and when He says, “We sent you to all people.” [Surah 34:28] "it is in the Raj’a.”
– Bihar Al-Anwar, Al-Allamah Al-Majlisi, Vol. 53, p. 42
On the commentary of the verse: "He is the One Who sent His Messenger with guidance and the religion of truth in order to prevail over all religions, even though the polytheists may be averse." [Surah 9:33], Al-Mufaddel ibn Omar asked Imam Al-Sadiq (PBUH): “O Master, didn’t the Messenger of Allah (PBUH & His Family) prevail over all religions?” He (PBUH) replied: “O Mufaddel! If the Messenger of Allah (PBUH & His Family) had prevailed over all religions, there wouldn’t have been any Magus, Jew, Sabian, or Christian, or any sect, or any disagreement, or doubt, or polytheism, or any idol worshippers, or idols Al-Lat and Al-Uzza, or any worshippers of the sun and moon, or of the stars, or fire or stones. Rather His saying, “In order to prevail over all religions.” is in the time of the Mahdi during the Raj’a, and this is His saying: "And fight them until there is no fitna and till religion is entirely to Allah.” [Surah 8:39]
– Bihar Al-Anwar, Al-Allamah Al-Majlisi, Vol. 53, pp. 33-34
The books of the Sunnah have narrations that mention the Return of the Prophet Mohammed (PBUH & His Family) as well.
Narrated 'Aisha: (the wife of the Prophet) Allah's Messenger died while Abu Bakr was at a place called As-Sunah (Al-'Aliya) 'Umar stood up and said, "By Allah! Allah's Messenger is not dead!" 'Umar (later on) said, "By Allah! Nothing occurred to my mind except that." He said, "Verily! Allah will resurrect him and he will cut the hands and legs of some men."
– Sahih Bukhari, Al-Bukhari, Book of Companions of the Prophet, Hadith No. 3667, 3668
Abu Huraira said: “When the Messenger of Allah (PBUH & His Family) passed away, Umar ibn Al-Khattab stood up and said: “There are hypocrites who allege that the Messenger of Allah has died. Verily, the Messenger of Allah did not die, but he went to his Lord as Moses, son of Imran, went to his Lord, for he was absent from his people 40 nights then he returned to them after it was said he had died. By Allah, the Messenger of Allah (PBUH & His Family) will return as Moses returned and he will cut the hands and legs of men who claimed that the Messenger of Allah has died”.
– Al-Sira Al-Nabawiyya, Ibn Hisham, 3rd ed., Vol. 4, p. 306 (Online book: p.1069-1070)
We can see from narrations such as these that the people of that era were speaking very candidly about the concept of the Prophet Mohammed (PBUH & His Family) returning to this world. This indicates that it should not be a far-fetched idea for the Muslim nation to believe that the soul of Prophet Mohammed (PBUH & His Family) returns during the end times.
Imam Ahmed Al-Hassan (From Him is Peace) has revealed that the Prophet Mohammed (PBUH & His Family) has indeed returned, as it was prophesied. He is the Twelfth Imam Mohammed ibn Al-Hassan Al-Askari, Al-Mahdi (PBUH & His Family), in his return.