To what extent is the Sufis' reliance on a hadith from Imam Ahmad ibn Hanbal's Musnad (Vol. 3, p. 152) valid in proving the permissibility of dancing around the Prophet, may Allah bless him and grant him peace, and why is dancing not permissible as a form of worship for them?

The Sufi group deviated from the methodology of the Prophet, peace and blessings be upon him. The mentioned hadith (The Sudanese played with shields and spears) does not indicate the permissibility of Sufi dancing, but rather the permissibility of playing with weapons and training for warfare for jihad. This is what Al-Bukhari translated and what scholars like Ibn Hajar and Al-Nawawi explained.

Dancing for men, in general, is not permissible because it is a custom of women. However, playing with weapons without dancing and drums is fine. Dancing accompanied by dhikr (remembrance of God) is among the innovated matters that neither the Prophet, peace and blessings be upon him, nor his companions did. Every act of worship that the Messenger and his companions did not perform is an innovation and a misguidance that is rejected.

There is no evidence for Sufi dancing accompanied by dhikr from the Quran, the Sunnah, or the practice of the Companions. It is an innovation that scholars and the four Imams have denounced, and its origin is derived from Judaism. The first to introduce it were the followers of the Samaritan around the calf, and it is the religion of disbelievers and calf-worshippers.