In the 2nd year (624 AD) after Hijra (migration) the Prophet (saws) received some gifts of homage from the Negus, King of Abyssinia. A signet ring, a pair of shoes and an ‘anaza (a short spear), and Bilal ibn Rabah (raa) was given the honour to walk infront of the Prophet (saws) on his way to Salat al-Eid and Salat-Istisqa (prayer for rain) carrying the spear.
Upon reaching the Musalla, Bilal Al-Habashi (the Abyssinia) (raa) would pitch the spear in the ground one or two yards infront of the Prophet (saws) saws.
The Two Festivals (Eids)
Bukhari :: Book 2 :: Volume 15 :: Hadith 89
Narrated Ibn Umar (raa): On the day of ‘Id-ul-Fitr and ‘Id-ul-Adha a spear used to be planted in front of the Prophet (saws) (as a Sutra for the prayer) and then he would pray.
Thus Bilal (raa), along with being the first muazzin of Islam had the honor of keeping the Prophets spear throughout his lifetime.
Call to Prayers (Adhaan)
Bukhari :: Book 1 :: Volume 11 :: Hadith 606
Narrated ‘Aun bin Abi Juhaifa:
My father said, "I saw Allah’s Apostle (saws) at a place called Al-Abtah. Bilal (raa) came and informed him about the prayer and then came out with an Anza and planted it in front of Allah’s Apostle (saws) at Al-Abtah and pronounced the Iqama."