The ahaadeeth about the Mahdi and the descent of ‘Eesa (peace be upon him) are not a reason to stop striving
Question

                Some people take the ahaadeeth about the Mahdi and the descent of ‘Eesa (peace be upon him) as a reason to stop striving for Islam, so they sit and wait for the emergence of the Mahdi or the descent of ‘Eesa, so that Islam and the Muslims will rise once again. What is your opinion of this understanding?.
Praise be to Allah.
    This miserable situation in which the Muslim ummah is today 
    is one that is disgraceful, and every Muslim is responsible for setting 
    things straight. But some Muslims fail to strive, relying on hope and 
    avoiding doing anything to set the ummah’s situation straight, on the 
    grounds that it was caused by those who came before us and will be set right 
    by those who come after us. So they fail to strive to support the religion 
    of Allaah, on the basis that the Mahdi is the one who will do that. 

    This is resorting to hope without implementing the means that 
    are prescribed in Islam. Allaah says (interpretation of the meaning): 

    “It will not be in accordance with your desires (Muslims), 
    nor those of the people of the Scripture (Jews and Christians), whosoever 
    works evil, will have the recompense thereof, and he will not find any 
    protector or helper besides Allaah”

    [al-Nisa’ 4:123]
This negativity from 
    which some Muslims are suffering nowadays is not something that could be 
    prescribed by the Islamic texts, rather it is a misunderstanding, 
    incapability and laziness, and an evasion of responsibility. 

    Allaah has commanded the Muslims to strive for this religion 
    and to call people to it, to debate with the kuffaar and invite them to 
    Islam with wisdom and beautiful preaching, and to fight them until there is 
    no longer any shirk on earth. Allaah says (Interpretation of the meaning): 

    “And fight them until there is no more Fitnah (disbelief 
    and polytheism, i.e. worshipping others besides Allaah), and the religion 
    (worship) will all be for Allaah Alone [in the whole of the world]. But if 
    they cease (worshipping others besides Allaah), then certainly, Allaah is 
    All-Seer of what they do”

    [al-Anfaal 8:39]
Ibn Katheer (may Allaah 
    have mercy on him) said: 

    Here Allaah commands us to fight the kuffaar “until there 
    is no more Fitnah” i.e., shirk, “and the religion (worship) will all 
    be for Allaah alone” i.e., the religion of Allaah will be the one that 
    prevails over all other religions. End quote. 

    This command is not specific to any particular time or place, 
    rather the Muslims at all times and in all places are commanded to do this. 
    Undoubtedly striving for Islam and supporting it on earth require the 
    Muslims to work hard, strive hard and implement all means that will lead to 
    that. 

    Some people misunderstand the ahaadeeth which speak of the 
    emergence of the Mahdi or the descent of the Messiah ‘Eesa ibn Maryam (peace 
    be upon him) and they become apathetic, and they sit waiting for the 
    emergence of the Mahdi or the descent of the Messiah, and they stop calling 
    people to Allaah and striving to make the word of Allaah supreme. But 
    Allaah, may He be exalted, and His Messenger  (peace and blessings of 
    Allaah be upon him) have commanded us to implement the means and strive on 
    this earth.  

    Allaah says (interpretation of the meaning): 

    “O you who believe! Take your precautions, and either go 
    forth (on an expedition) in parties, or go forth all together”

    [al-Nisa’ 4:71] 

    “And make ready against them all you can of power, 
    including steeds of war (tanks, planes, missiles, artillery) to threaten the 
    enemy of Allaah and your enemy”

    [al-Anfaal 8:60]

    “He it is Who has made the earth subservient to you (i.e. 
    easy for you to walk, to live and to do agriculture on it); so walk in the 
    path thereof and eat of His provision. And to Him will be the Resurrection”

    [al-Mulk 67:15] 
“and for this let (all) 
    those strive who want to strive (i.e. hasten earnestly to the obedience of 
    Allaah)”

    [al-Mutaffifeen 83:26]

    “For the like of this let the workers work”

    [al-Saaffaat 37:61] 
“And whoever desires the 
    Hereafter and strives for it, with the necessary effort due for it (i.e. 
    does righteous deeds of Allaah’s obedience) while he is a believer (in the 
    Oneness of Allaah  
    Islamic Monotheism) — then such are the ones whose striving shall be 
    appreciated, (thanked and rewarded by Allaah)”
    [al-Isra’ 17:19]

    “And take a provision (with you) for the journey, but the 
    best provision is At-Taqwa (piety, righteousness)”

    [al-Baqarah 2:197]

    The Messenger of Allaah  (peace and blessings of Allaah 
    be upon him) used to make preparations for everything, drawing up a plan, as 
    happened during the hijrah, when he prepared mounts and a guide, and chose a 
    traveling-companion, and he decided on a place to hide until the pursuit had 
    cooled down, and he shrouded all of that in secrecy. This is how he acted in 
    all his campaigns, and this is how he trained his noble companions. They 
    used to prepare themselves with all kinds of weapons. The Messenger of 
    Allaah  (peace and blessings of Allaah be upon him) entered Makkah with 
    his helmet on his head, although Allaah had said (interpretation of the 
    meaning): 

    “Allaah will protect you from mankind”

    [al-Maa'idah 5:67] 
And when he traveled for 
    jihad or Hajj or ‘Umrah, he took his provisions with him. 

    The Prophet  (peace and blessings of Allaah be upon him) 
    said: “Strive for that which will benefit you, and seek the help of Allaah, 
    and do not be helpless.” Narrated by Muslim, 2664.  

    We can imagine what the fate of the da’wah and the ummah 
    would have been if the previous generations had heeded the calls to give up 
    until the Mahdi emerges. Would they have defeated the Tatars and crusaders, 
    or conquered Constantinople? 

    This misunderstanding of the Islamic texts which speak about 
    the Mahdi and the Messiah (peace be upon him) has been refuted by many 
    scholars, daa’iyahs and writers. 

    Shaykh al-Albaani (may Allaah have mercy on him) said: 

    It is not permissible for the Muslims to ignore striving for 
    Islam and the establishment of an Islamic state on earth, waiting for the 
    emergence of the Mahdi and the descent of ‘Eesa (peace be upon them), out of 
    despair or imagining that that is not possible before they come. This is a 
    false notion and false despair. Allaah and His Messenger  (peace and 
    blessings of Allaah be upon him) did not tell us that Islam will not return 
    or regain power on earth except at their time. It is possible to achieve 
    that before they come, if the Muslims implement the means of doing that, 
    because Allaah says (interpretation of the meaning): 

    “O you who believe! If you help (in the cause of) Allaah, 
    He will help you, and make your foothold firm”

    [Muhammad 47:7] 

    “Verily, Allaah will help those who help His (Cause)”

    [al-Hajj 22:40]
With regard to the 
    ahaadeeth which speak of the descent of ‘Eesa (peace be upon him) etc., it 
    is obligatory to believe in them, and to refute those who think that they 
    mean we should not strive, and to prepare to do whatever must be done at any 
    time and in any place. End quote. 

    Professor ‘Abd al-‘Azeez Mustafa said: 

    Striving in jihad against the kuffaar, no matter who they are 
    and no matter where they are and no matter in what time they are, is 
    obligatory according to sharee’ah, and this has not been abrogated. This is 
    an established Islamic truth. This jihad is obligatory if the conditions for 
    it are met and if the guidelines and rulings concerning it apply. It is not 
    one of these conditions, guidelines or rulings that jihad should be delayed 
    until the prediction (about the Mahdi and the Messiah) is fulfilled, and 
    this is not how the first Muslims understood it or acted. When they were 
    told that Allaah would break the power of Chosroes with their swords, they 
    did not hide in their houses waiting for that prediction to come true and 
    for it to come to pass without them making any effort; rather they made 
    preparations for that until victory came to pass. Thus the consequences of 
    obeying the command of Allaah (i.e., to fight the kuffaar) coincided with 
    the decree of Allaah (i.e., that their kingdom should be destroyed). But 
    some Muslims nowadays say: No, jihad against the Jews should not happen 
    until the Dajjaal appears. Perhaps this is part of the fitnah of the Dajjaal 
    in this world. 

    This foolish notion has taken hold of some Muslim youth, and 
    they have refused to take any responsibility with regard to al-Masjid 
    al-Aqsa, the environs of which Allaah has blessed. An even more foolish 
    notion has taken hold of them, which is that the Islamic state and the 
    caliphate can never be established until the Mahdi emerges. 

    It is a very strange idea. By their actions it is as if they 
    are saying to the Jews: Treat your enemies harshly, and saying to the 
    Christians: Continue with your wrongdoing… and to the Muslims: Continue with 
    your division and conflicts… until the Mahdi emerges. I do not know on what 
    evidence they have fallen into this error and why they imagine that the 
    Mahdi will emerge to people who are doing nothing or that apathetic people 
    will support him. 

    We ask Allaah to bring the Muslims back to their religion. 

    And Allaah knows best.  

    See: al-Mahdi wa Fiqh Ashraat al-Saa’ah by Shaykh Muhammad ibn Isma’eel al-Muqaddim.