What is Sufism?
Sufism is a sects of Islam that was started shortly after the time of the prophet. It is often referred to as “Islamic mysticism”, but this is an incorrect way of describing this sect. This sects does follow the Quran and the teachings of the Prophet Muhammad ﷺ, but they have added their own traditions and practices in a way of being more connected to Allah. This includes dancing and music. This sects has been heavily influenced by Christian monasticism and Neoplatonism (A school of Greek philosophy).
What's wrong with Sufism?
This issue with this sects is it practices innovation, in the following Hadith, the Prophet Muhammad ﷺ prohibits innovation in Islam.
It was narrated that 'Abdullah bin 'Abbas said: "The Messenger of Allah (ﷺ) said: 'Allah refuses to accept the good deeds of one who follows innovation until he gives up that innovation.'"
This also contradicts the Quran, where Allah says that with Islam, he has perfected for us our religion. This means nothing new can be added or removed from Islam.
"Today I have perfected your faith for you, completed My favour upon you, and chosen Islam as your way."
Final Note
We’ve establish that this sect, while follows the Quran and Sunnah, uses innovation. Not only does this contradict the Quran, but the Prophet Muhammad ﷺ prohibited this.
We are all Muslim, do not separate yourselves into sects and “do not commit excess in your religion” Quran 4:171. Keep it simple and follow in the footsteps of our Prophet Muhammad ﷺ.