Sheikh Abul Hasan Ali Nadvi Rahimullah writes

(Translation of excerpts from Sheikh Urdu Book available here)

Teaching and Learning of deen and its effort is integral part of muslim life.
"It is very clear from Quran and Hadith that following is a parts and parcel of a Muslim life.
1.To learn deen for oneself and to practice it in life.
2.To Teach deen (Islamic Knowledge and Practice) to others
3.Encouraging for good and forbidding from bad
4.Striving for the Spread and Propagation of deen. These all should be parts of a Muslim life.
In the era of prophet and early generation of Muslim people of all walk of life i.e Farmers businessman rich or poor used to spare some time for learning and teaching deen.
He was a businessman or farmer but whenever demanded he was ready to postpone these engagement for the sake of deen. Those who could not do this. Surah Tauba is full with the stern warning for them. (It is actually warning for all of Muslims till the day of judgment)
Hazrat Kaab bin Malik Raziallahu Anhau who could not participate in TABOOK. He was so much disapproved that the same engagements and the city of Madeenah became a thorn for him. He was so much boycotted that no one in the city was even to talk with him and to reply him.
A Down Revolution was to consider service of deen as Public work than Personal work.
A back revolution has happened today (Both Ideological and Practical). Now striving in the service of deen is not continuing to be a part of life of a general Muslim.
Rather these have become a public work of Ummat e Muslimah and not of individual Muslims. Some special people has been assigned and engaged for the service of deen. General Muslims got an excuse and became free from service and striving personally for the sake of deen.
(1.People give some donations to Madarsas and for charity work for benefit etc that’s all. This is very good but it is not satisfactory at all. 2.Muslim ummah in general has no direct personal active or even emotive involvement in the sevice of deen. 3.Obviously many Muslims are offering five times prayer and giving Zakat and Hajj but these are obligatory prayers and not the active service of deen)
The Quran has praised the Muslims in these words.
وَالْمُؤْمِنُونَ وَالْمُؤْمِنَاتُ بَعْضُهُمْ أَوْلِيَاءُ بَعْضٍ يَأْمُرُونَ بِالْمَعْرُوفِ وَيَنْهَوْنَ عَنْ الْمُنكَرِ وَيُقِيمُونَ الصَّلاَةَ وَيُؤْتُونَ الزَّكَاةَ وَيُطِيعُونَ اللَّهَ وَرَسُولَهُ أُوْلَئِكَ سَيَرْحَمُهُمُ اللَّهُ إِنَّ اللَّهَ عَزِيزٌ حَكِيمٌ (التوبة: 71).
[9:71]
The believers, male and female, are friends to each other. They bid virtue and forbid vice and establish Salah and pay Zakah and obey Allah and His Messenger. Those are the ones whom Allah will bless with mercy. Surely, Allah is Powerful, Wise.
In this Ayat these qualities has been described with Emaan indicating these are common work for all Muslims associated with his Emaan and not special work. (Momineen ke umoomi kaam aur Emaan ki Illat hain)

This change was a practical turning point
In the life of current Muslims compared to the life of Sahaba and first few generations of Muslims this was a change or deletion of an important act.
Among Sahaba there was no exception and there was no segregation for the services of deen. (ISTASHNA AUR TAKHSEES).Rather all Muslim was involved in the service of deen according to his/her capability and competence.
(Among sahaba also people were of different capabilities with respect to wordly life like rich or poor,farmer buisenessman labourers etc were there and with respect to deen also more knowledgeable and less knowledgeable but all Sahab was involved in the service of deen according to his ability.)
Service of deen was common to all and no Farmer or businessman or labourer was an exception.
And when some Ansars Shaba Karam thought of taking some rest from Effort of deen and Jihad for caring their business and farms. There Point was “Now Alhamdulillah Islam has spreaded and many supporters and caretakers of Islamic services has come up”
Then Allah sends the Ayat
وَلاَ تُلْقُوا بِأَيْدِيكُمْ إِلَى التَّهْلُكَةِ
do not put yourselves into destruction [2:195]
(Riwayat Abu Ayyub Ansari in Abu Dawood tirmizi nasaee)
It is like to keep away themselves from service of Deen and the propagation of the message of Allah was a self harming suicidal action.............."