“The presence of the kings of Islam is a great blessing from Allah… You should know that the country of Hindustan is a large land. In olden days, the kings of Islam had struggled hard and for long in order to conquer this foreign country. They could do it only in several turns…
Every (Muslim) king got mosques erected in his territory, and created madrasas. Muslims of Arabia and Ajam (non-Arab Muslim lands) migrated from their own lands and arrived in these territories. They became agents for the publicity and spread of Islam here. Uptil now their descendants are firm in the ways of Islam…Among the non-Muslim communities, one is that of the Marhatah (Maratha). They have a chief. For some time past, this community has been raising its head, and has become influential all over Hindustan…
…It is easy to defeat the Marhatah community, provided the ghãzîs of Islam gird up their loins and show courage…
In the countryside between Delhi and Agra, the Jat community used to till the land. In the reign of Shahjahan, this community had been ordered not to ride on horses, or keep muskets with them, or build fortresses for themselves. The kings that came later became careless, and this community has used the opportunity for building many forts, and collecting muskets…
In the reign of Muhammad Shah, the impudence of this community crossed all limits. And Surajmal, the cousin of Churaman, became its leader. He took to rebellion. Therefore, the city of Bayana which was an ancient seat of Islam, and where the Ulama and the Sufis had lived for seven hundred years, has been occupied by force and terror, and Muslims have been turned out of it with humiliation and hurt…
…Whatever influence and prestige is left with the kingship at present, is wielded by the Hindus. For no one except them is there in the ranks of managers and officials. Their houses are full of wealth of all varieties. Muslims live in a state of utter poverty and deprivation. The story is long and cannot be summarised. What I mean to say is that the country of Hindustan has passed under the power of non-Muslims. In this age, except your majesty, there is no other king who is powerful and great, who can defeat the enemies, and who is farsighted and experienced in war. It is your majesty’s bounden duty (farz-i-ain) to invade Hindustan, to destroy the power of the Marhatahs, and to free the down-and-out Muslims from the clutches of non-Muslims. Allah forbid, if the power of the infidels remains in its present position, Muslims will renounce Islam and not even a brief period will pass before Muslims become such a community as will no more know how to distinguish between Islam and non-Islam. This will be a great tragedy. Due to the grace of Allah, no one except your majesty has the capacity for preventing this tragedy from taking place.
We who are the servants of Allah and who recognise the Prophet as our saviour, appeal to you in the name of Allah that you should turn your holy attention to this direction and face the enemies, so that a great merit is added to the roll of your deeds in the house of Allah, and your name is included in the list of mujãhidîn fi Sabîlallah (warriors in the service of Allah). May you acquire plunder beyond measure, and may the Muslims be freed from the stranglehold of the infidels. I seek refuge in Allah when I say that you should not act like Nadir Shah who oppressed and suppressed the Muslims, and went away leaving the Marhatahs and the Jats whole and prosperous.
The enemies have become more powerful after Nadir Shah, the army of Islam has disintegrated, and the empire of Delhi has become childrens’ play. Allah forbid, if the infidels continue as at present, and Muslims get (further) weakened, the very name of Islam will get wiped out.
…When your fearsome army reaches a place where Muslims and non-Muslims live together, your administrators must take particular care. They must be instructed that those weak Muslims who live in the countryside should be taken to towns and cities. Next, some such administrators should be appointed in towns and cities as would see to it that the properties of Muslims are not plundered, and the honour of no Muslim is compromised.”

Letter to Ahmad Shah Abdali, Ruler of Afghanistan. Translated from the Urdu version of K.A. Nizami, Shãh Walîullah Dehlvî ke Siyãsî Maktûbãt, Second Edition, Delhi, 1969, p.83 ff.
From his letters