Al-Nawawi’s description of some of his teachers as Sufis and its meaning

Question:
The questioner says: The Imam al-Nawawi (may Allah have mercy on him) states in his introduction to his commentary on Sahih Muslim, when mentioning the chains of his teachers in transmitting Sahih Muslim, that he describes some of his teachers as Sufis. Does he mean the Sufism known today, or something else?

Answer:
Yes, he means the known Sufism, but the Sufism of the early generations. The Sufism of the early generations is lighter than the Sufism of the later generations, because the Sufism of the early generations was merely striving in worship and asceticism, and they had no religious innovations or superstitions. As for the Sufism of the later generations, religious innovations and superstitions entered into it; indeed, disbelief and shirk (associating partners with Allah) entered into it, along with calling upon other than Allah and worshipping other than Allah. The Sufism that Muslim refers to is of the light kind, like the Sufism of al-Fudayl ibn 'Iyad (may Allah have mercy on him) and al-Junayd. This is light Sufism, meaning striving in worship and asceticism, and leaving some permissible things in order to devote oneself to worship. This, although it is better, does not reach the level of the forbidden Sufism of today, the vile Sufism that has now reached shirk, disbelief, and atheism.