Why did Ibn Hajar Al-Aslami send a she-camel to the Prophet, may Allah bless him and grant him peace, before his conversion to Islam? And what is the meaning of the Prophet's command to him: "Brand the camels on their necks with the mark of a horse's tether, which is two circles with a line extending between them, for that is their mark"?

The summary of the answer:

Al-Haythami, Ibn Abd al-Barr, Al-Hafiz, and Ibn Hisham narrated the story of the Prophet's (peace and blessings be upon him) passage during the Hijra by Aws ibn Hajar al-Aslami, who carried the Prophet and Abu Bakr on a camel called "Ibn al-Rida'," and sent with them his servant Mas'ud ibn Hunaydah. There was disagreement regarding Aws's name, whether he was Aws ibn Hajar or Aws ibn Abdullah ibn Hajar al-Aslami, and his kunya, whether it was Abu Tamim or Abu Aws. Aws performed a favor for the Prophet (peace and blessings be upon him), just as Umm Ma'bad and Mut'im ibn Adi did. "Qayd al-Faras" (horse's tether) is a mark or brand on camels, distinguishing them from others' camels.