Salam,
Alot of times when he sends these they relate to the day he sends them…so I am sure you can tell that he sent this on Eid al Ghadeer.
In the Name of Allah, the Most Beneficent, the Most Merciful
Hadith 73:
Prophet Muhammad (pbuh&hp): Verily, I am leaving behind two weighty things amongst you, which if you strongly adhere to both, you shall not go astray after me: the Book of Allah, which is a rope stretched from Heaven to Earth, and my kindred (Itrat) who belong to my household (Ahl al-Bayt), for indeed, the two will never separate until they come back to me by the Pond (of al- Kawthar on the Day of Judgement). Beware of how you behave towards them after my departure, for Allah, the Merciful, has informed me that these two (i.e., Quran and Ahl al-Bayt) shall never separate from each other until they reach me in Heaven at the Pond (of al-Kawthar). I remind you, in the name of Allah, about my Ahl al-Bayt. I remind you, in the name of Allah, about my Ahl al-Bayt. Once more! I remind you, in the name of Allah, about my Ahl al-Bayt.