What is nisbah (nisbat) in Sufism?

The word nisbah, also written nisbat, means affinity or connection, and in Tasawwuf it denotes the affinity between Allah and the seeker. The essence is that the seeker should develop virtues to an extent that they should permeate through him. When those virtues become an essential part of one's being, it can be termed spiritual affinity.

The Companions and the ones who came after them used to obtain spiritual affinity through consistency and regularity in the performance of the obligatory prayers, voluntary prayers, dhikr, recitation of the Qur'an, remembrance of death and the fear of the Day of Judgment. This led to the state of perpetual piety known as taqwa, and they guarded this affinity.

In Tasawwuf, nisbah is the connection to Allah's Messenger ﷺ and finally with Allah, where every true shaykh takes his disciples to follow in the steps of Allah's Messenger ﷺ. Affinity is explained in the hadith narrated by Anas may Allah be pleased with him, that the Prophet ﷺ stated as a part of a lengthy discourse, "No servant ever, approaches Allah in complete sincerity except that Allah makes the hearts of the believers incline towards that person with love and care; while Allah is the first to bring that person every manner of goodness." [al-Haythami, Majma az-Zawaid 10/247, as quoted in Thanvi, Haqiqat al-Tariqa min as-Sunna al-Aniqa 205]

As explained by the scholars, there are two essentials for the heart to be filled with the Divine Light: constant remembrance and constant obedience. Under most conditions, this is said to be the essence of internal affinity, and the hadith above alludes to this affinity.

Another hadith refers to the harmony between the souls, as reported on the authority of Abu Huraira may Allah be pleased with him, that Allah's Messenger ﷺ said, "The souls of humankind were (in the spirit world) as an army gathered. Then those who were acquainted with one another (in that world) will harmonise (in this world), and those who were unknown to one another they will fall into discord here." [Sahih Muslim, Sunan Abi Dawud]

In the first stage of affinity, love for Allah's Messenger ﷺ is acquired and the heart is cleansed to a degree, but the connection is still weak. For as long as the person stays in the company of the shaykh the connection is strong, but upon leaving that company it diminishes, just like an electronic object that works for as long as the power is connected. This first stage is called Nisbat e Inekasi, or reflective affinity.

The second stage is called Nisbat e Ileqai, or inspirational affinity, where the connection is stronger than in the first stage but needs to be revived to stay connected. The same example of an electronic object holds, but in this case the object can hold the charge for some time before it needs to be recharged. The third stage is Nisbat e Islahi, or reformative affinity, where the connection becomes steady as a continuous flow. [Shah, Umdatul Sulook]

The fourth stage is the one which Abu Bakr may Allah be pleased with him had with Allah's Messenger ﷺ, called Nisbat e Ittahadi, or associative affinity, where the disciple becomes an image of his shaykh in all aspects.