What is the relationship between the Hadith of the dispute of the Exalted Assembly and the ذؤابة (forelock/tassel), as mentioned by Ibn al-Qayyim in Zad al-Ma'ad, and what is the source of the benefit mentioned by Ibn Taymiyyah regarding the reason the Prophet (peace be upon him) adopted it?

The ذؤابة (dhu'abah) is the tail of the turban. The Prophet, peace and blessings be upon him, used to let it hang down between his shoulders, as narrated by Al-Tabarani from Ibn 'Umar, and by Muslim from 'Amr ibn Hurayth. Ibn al-Qayyim, quoting his teacher Ibn Taymiyyah, connected the hanging down of the dhu'abah with the Prophet's vision of his Lord placing His hand between the Prophet's shoulders, and so the Prophet, peace and blessings be upon him, honored that place with the 'adhbah (turban tail).