Praise be to Allah.
The Prophet (peace and blessings of Allah be upon him) told us of signs that will take place before the Hour begins (qiyamah signs), which the scholars have categorized as “lesser signs” and “greater signs”. Some of them designated a third category, “intermediate signs”, namely the emergence of the Mahdi. This is one of the minor signs, but during his time some of the major signs will appear.
The Prophet (peace and blessings of Allah be upon him) has told us of some of the things that will distinguish the believers from the kaafirs before the Day of Resurrection. These include:
(a) The emergence of the Beast.
Allah says (interpretation of the meaning):
“And when the Word (of torment) is fulfilled against them, We shall bring out from the earth a beast for them, to speak to them because mankind believed not with certainty in Our Ayaat (Verses of the Qur’aan and Prophet Muhammad)”
Ibn Katheer said:
This Beast will emerge at the end of time, when people have become corrupt and forsaken the commands of Allah, and altered the true religion. Then Allah will bring forth to them a Beast from the earth.”
Tafseer Ibn Katheer
It was narrated from Abu Umaamah that the Prophet (peace and blessings of Allah be upon him) said: “The Beast will emerge and strike the people on their noses, then their numbers [i.e., those who have been marked on the nose] will increase among you until a man will buy a camel, and they will say, ‘Who did you buy it from?’ and he will say, ‘I bought it from one of those with a mark on their noses.’”
Narrated by Ahmad, 21805. Classed as saheeh by Shaykh al-Albaani in al-Silsilah al-Saheehah, 322.
What is meant by striking the people on their noses is that it will make marks on their noses, and there will be one mark for believers and another for kaafirs.
It was narrated from Abu Hurayrah that the Prophet (peace and blessings of Allah be upon him) said: “There are three things which, when they emerge, no good will it do to a person to believe then, if he believed not before, nor earned good (by performing deeds of righteousness) through his Faith [cf. al-An’aam 6:158]: the sun rising from the west, the Dajjaal and the Beast of the earth.”
Narrated by Muslim, 158.
(b) The followers of the Dajjaal when he emerges.
It was narrated from Anas ibn Maalik that the Messenger of Allah (peace and blessings of Allah be upon him) said: “Seventy thousand of the Jews of Isbahaan wearing large cloaks will follow the Dajjaal.”
(c) Madeenah will be cleansed of kaafirs and hypocrites at the time of the Dajjaal.
It was narrated from Anas ibn Maalik (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: “There is no city that the Dajjaal will not enter, except Makkah and Madeenah. He will not approach any of their alleyways but there will be angels standing guarding it. Then Madeenah will be shaken with its people three times, and Allah will bring forth every kaafir and hypocrite.”
Narrated by al-Bukhaari, 1782; Muslim, 2943.
(d) A wind blowing from the direction of Yemen
It was narrated that Abu Hurayrah said: The Messenger of Allah (peace and blessings of Allah be upon him) said: “Allaah will send a wind from Yemen, softer than silk, and it will not leave anyone in whose heart is faith the weight of a grain but it will take him (his soul).”
Narrated by Muslim, 117.
With regard to the meaning of this hadeeth, there are many similar ahaadeeth, for example: “the Hour will not begin until it is not said on earth, ‘Allah, Allah’”; and “It will not come upon anyone who says, ‘Allah, Allah’”; and “It will only come upon the most evil of people.” All of these and similar reports mean what they appear to mean.
With regard to the other hadeeth, “A group of my ummah will continue to follow the truth [?] until the Day of Resurrection,” this does not contradict the other ahaadeeth, because what this means is that they will continue to adhere to the truth until their are taken by that gentle wind, close to the time of the Hour or when its portents appear.
So the mention in this hadeeth of them remaining until the Hour begins is to be understood as referring to when its portents appear and it is about to begin.
Sharh Muslim, 2/132.
And Allah knows best.
(Source – Islam Q&A)