How much a Muslim should Sacrifice for Deen and Islam, Allah has purchased from believers lives and property Quran chaptor Surah Tauba verse Ayat no 110 Arabic text and English translation

Although it is ambit clear that this 40 days and 4 month are not a sharaee ruling. It is just tarteeb/system. Otherwise their will be so many problems like Family will not be knowing when the person is returning back.
Only after going in the path of Allah you will taste these difficulties and its Reward.
Still while fixing the days the elders of Tabligh has tried that there should be some relation from Quran and Hadith. 
Here we are Presenting some Ayats of Quran and Ahadith that establish some numerical Value of 40 days and 4 months.
40-Days from Quran
Allah (ta’ala) mentions in Surah Baqarah verse 51: "We appointed 40-nights for Musa.." (wa Idh wa adna Musa arbaain laylatan ….). This verse establishes the numerical value and importance of 40days. 
40-Days from the Hadith
It will make this nice and easy for the critics. Imaam Tirmidhi (rahmatullahi alayhi) has recorded the following hadith:
"Whoever prays to Allah for forty-days in congregation, reaching the opening Takbeer, will have immunity from two things: freedom from the Fire and freedom from hypocrisy."
(Hasan by Tirmidhi, and also by Salafi Scholar al-Albani in Saheeh al-Jaami' (6365).)
('An Anas ibn Maalikin [radhi allahu anhu] qaala, Qaala rasullulahi [sallahu alayhi wa sallam]: man salla lillahi 'arba'aina yauman fee jamaatin yudriku-takbeerata al-ulaa kutibaa lahu baraa-ataani, baraa-atun min-nan naar wa baraa-tun min-nan nifaaqi) - Rawahu Tirmidhi
What we should ask ourselves is, "have we acted according to this hadith knowing well that it brings immunity from Hypocrisy and fire of Hell?" 
This is the manhaj (way) of the messenger of Allah (sallahu alayhi wa sallam) that has been implemented in the work of Tablighi Jamaat. 
Spending some time out of our busy schedules to get closer to Allah (ta'ala) and His beloved messenger (sallahu alayhi wa sallam) is literally called "fee-sabeelillah" (in the path of Allah).
Imaam Bukhari (rahmatullahi alayhi) has mentioned a hadith [more or less] that whomsoever goes in the path of Allah (fee-sabeelillah) and dust gathers on their feet, then Allah will forbid the fire of Hell on them. This hadith was put under the Chapter of Juma'a and Imaam Bukhari has applied it to all Muslims going for Juma Prayers:
حدثنا علي بن عبد الله قال: حدثنا الوليد بن مسلم قال: حدثنا يزيد بن أبي مريم قال: حدثنا عباية بن رفاعة قال:
أدركني أبو عبس، وأنا أذهب إلى الجمعة، فقال: سمعت النبي صلى الله عليه وسلم يقول: (من اغبرت قدماه في سبيل الله حرمه الله على النار
There is not a single shred of evidence to suggest that this hadith was narrated by the messenger of Allah (sallahu alayhi wa sallam) regarding "Juma'a". 
However, Imaam Bukhari has included this in this chapter because "fee sabeelillah" is a broad word. Similarly, when people "go out" (root word Kharaja: noun - Khurooj) in the "path of Allah" (fee-sabeelillah) for 40-days they not only get the rewards mentioned in Imaam Bukhari's Sahih but are also practicing the hadith of Imaam Tirmidhi (rahmatullahi alayhi).
How much we should sacrifice?
Let us ask the fundamental question, 
"How much time & sacrifice should Muslims put-in (or sacrifice) for the pleasure of Allah so that we are closer to the practice (manhaj) of the sahaba?"

Allah has asked lives and property 
إِنَّ اللَّهَ اشْتَرَىٰ مِنَ الْمُؤْمِنِينَ أَنفُسَهُمْ وَأَمْوَالَهُم بِأَنَّ لَهُمُ الْجَنَّةَ ۚ يُقَاتِلُونَ فِي سَبِيلِ اللَّهِ فَيَقْتُلُونَ وَيُقْتَلُونَ ۖ وَعْدًا عَلَيْهِ حَقًّا فِي التَّوْرَاةِ وَالْإِنجِيلِ وَالْقُرْآنِ ۚ وَمَنْ أَوْفَىٰ بِعَهْدِهِ مِنَ اللَّهِ ۚ فَاسْتَبْشِرُوا بِبَيْعِكُمُ الَّذِي بَايَعْتُم بِهِ ۚ وَذَٰلِكَ هُوَ الْفَوْزُ الْعَظِيمُ
Indeed, Allah has purchased from the believers their lives and their properties [in exchange] for that they will have Paradise. They fight in the cause of Allah , so they kill and are killed. [It is] a true promise [binding] upon Him in the Torah and the Gospel and the Qur'an. And who is truer to his covenant than Allah ? So rejoice in your transaction which you have contracted. And it is that which is the great attainment. 

Surah Tauba verse Ayat no 110
The expedition of Tabook - in which every Muslim in Madina was requested to contribute for the pleasure of Allah.
1. Sayyidna Abu Bakar (radhi Allahu anhu) contributed 100% of everything he had. Are there any Muslims like Abu Bakr (ra) today?or even cose!!!!!!!!!! Maybe; far and few!
2. Sayyidna Umar (radhi Allahu anhu) contributed 50% (1/2) of everything he had. Are there any Muslims like Umar (ra) today?or even cose!!!!!!!!!! Maybe; far and few!
3. Sayyidna Usmaan (radhi Allahu anhu) contributed 33% (1/3rd) of whole expenditure of the Army.
Anyone doing that?Even any figure closer to that..............

 Ask yourself this question. 8hrs should include, as a minimum, all the 5 obligatory prayers and extra prayers that are around the clock, including tahajjud prayers, zikr, recitation of the Quran, teaching and learning - self and family, visiting Muslims, entertaining guests, visiting the sick and any actions that are for the pleasure of Allah.