Urdu lecture summarized below:
Ihsan is also called Zuhd in the Quran. It involves turning one's attention away from the world and towards the Hereafter. No matter how pious one becomes, he or she still has needs that must be fulfilled. For example, a person will only eat if he has the means to purchase food, so some attachment to money will always exist, because it is the means of fulfilling ones needs. Zuhd involves overcoming greed for money (and other material and immaterial needs and desires).
Ihsan and zuhd are also called tasawwuf. This name derives from people who dressed in wool, which is called soof in Arabic. These people were known as sufis. They adopted a simple, ascetic lifestyle. Such asceticism is a feature of many other religions as well. The Hindus have ascetics called yogis. The Christians have ascetics called rahibs. The Buddhists also have ascetics who live in monasteries. All of these ascetics undergo exercises of self deprivation to overcome greed for worldly needs and pleasures. In the Middle Ages of Islam, the deen in its pristine form had become concentrated only among the scholars (ulama). The sufis lacked strong foundations in the teachings of Islam, and as a result, many ascetic practices from outside Islam became part of tasawwuf, such as praying while standing on one's head, and visualising one's spiritual master when engaged in contemplation and meditation.
The akabir ulama of Deoband (particularly Maulana Rasheed Ahmad Gangohi RA) reformed tasawwuf by removing everything from it that was alien to the Shariah. Unfortunately, stories of the sufis from the Middle Ages of Islam persist even in the tasawwuf of Deoband, and this is a deficiency that must be rectified.
People of the Jamaat e Islami and the Ahle Hadeeth are opposed to tasawwuf (primarily because of the distortion in the field during the Middle Ages of Islam). Pristine tasawwuf devoid of foreign practices (as practised by the akabir ulama of Deoband and their predecessors) is expounded in the opus of Shah Waliullah RA, called Hujjatullah Al-baligha. Mufti Saeed Palanpuri RA compiled a detailed commentary of this book and gifted it to a senior professor in Canada who taught this book at university. This professor (Maulana Wasi Akhtar Nadwi RA) was a staunch follower of the Jamaat e Islami. On reading about tasawwuf as explained in Hujjatullah Al-baligha, he conceded that this is the tasawwuf that everyone needs to follow.