It is said that the Shariat prospers under the shadow of the sword (al-Shara‘ tahat al-saif). And the glory of the holy Shariat depends on the kings … - Ahmad Sirhindi

Islam and infidelity (kufr) contradict one another. To establish the one means eradicating the other, the coming together of these contradictories being impossible. Therefore, Allah has commanded his Prophet to wage war (jihad) against the infidels, and be harsh with them. The glory is Islam consists in the humiliation and degradation of infidels and infidelity. He who honours the infidels, insults Islam. Honouring (the infidels) does not mean that they are accorded dignity, and made to sit in high places. It means allowing them to be in our company, to sit with them, and talk to them. They should be kept away like dogs. If there is some worldly purpose or work which depends upon them, and cannot be served without their help, they may be contacted while keeping in mind all the time that they are not worthy of respect. The best course according to Islam is that they should not be contacted even for worldly purposes. Allah has proclaimed in his Holy Word (Quran) that they are his and his Prophet’s enemies. And mixing with these enemies of Allah and his Prophet or showing affection for them, is one of the greatest crimes…
…The abolition of jizyah in Hindustan is a result of friendship which (Hindus) have acquired with the rulers of this land… What right have the rulers to stop exacting jizyah? Allah himself has commanded imposition of jizyah for their (infidels’) humiliation and degradation. What is required is their disgrace, and the prestige and power of Muslims. The slaughter of non-Muslims means gain for Islam… To consult them (the kafirs) and then act according to their advice means honouring the enemies (of Islam), which is strictly forbidden…
The prayer (=goodwill) of these enemies of Islam is false and fruitless. It should never be called for because it can only add to their numbers. If the infidels pray, they will surely seek the intercession of their idols, which is taking things too far… A wise man has said that unless you become a maniac (diwanah) you cannot attain Islam. The state of this mania means going beyond considerations of profit and loss. Whatever one gains in the service of Islam should suffice…

Cow-sacrifice in India is the noblest of Islamic practices. The kafirs [Hindus] may probably agree to pay jizya but they shall never concede to cow-sacrifice…. The real purpose in levying jizya on them [Hindus] is to humiliate then to such an extent that, on account of fear of jizya, they may not be able to dress well and to live in grandeur. They should constantly remain terrified and trembling. It intended to hold them under contempt and to uphold the honor and might of Islam.

Therefore, it is necessary that infidelity should be cursed in order to serve the faith (Islam). Cursing unbelief in the heart is the lesser way. The greater way is to curse it in the heart as well as with the body. In short, cursing means to nourish enmity towards enemies of the true faith, whether that enmity is harboured in the heart when there is fear of injury from them (infidels), or it is harboured in the heart as well as served with the body when there is no fear of injury from them.
In the opinion of this recluse, there is no greater way to obtain the blessings of Allah than to curse the enemies of the faith (be impatient with them). For Allah himself harbours enmity towards the infidels and infidelity…
Once I went to visit a sick man who was close to death. When I meditated on him, I saw that his heart was layered with darknesses. I intended to remove those darknesses. But he was not yet ready for it… When I meditated more deeply, I discovered that those darknesses had gathered due to his friendship with the infidels. They could not be dispersed easily. He had to suffer torments of hell before he could get purged of them…