Narrated as-Saib al-Makhzumi (RA):

That he was the partner of the Prophet (ﷺ) before the Prophethood. Then, he came (to Makkah) on the day of the Conquest (of Makkah), and he (the Prophet) said: "Welcome to my brother and partner." [Reported by Ahmad, Abu Dawud and Ibn Majah].

وَعَنْ اَلسَّائِبِ [ بْنِ يَزِيدَ ] اَلْمَخْزُومِيِّ { أَنَّهُ كَانَ شَرِيكَ اَلنَّبِيِّ ‏- صلى الله عليه وسلم ‏-قَبْلَ اَلْبَعْثَةِ, فَجَاءَ يَوْمَ اَلْفَتْحِ, فَقَالَ: " مَرْحَباً بِأَخِي وَشَرِيكِي } رَوَاهُ أَحْمَدُ, وَأَبُو دَاوُدَ, وَابْنُ مَاجَةَ [1]‏ .‏