The first to make their Islam public were seven

It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that the first to make their Islam public were seven people: the Messenger of Allah (peace and blessings be upon him), Abu Bakr, Ammar, his mother Sumayyah, Suhayb, al-Miqdad and Bilal (may Allah be pleased with them). As for the Messenger of Allah (peace and blessings be upon him), Allah protected him through his uncle Abu Talib; and Abu Bakr (may Allah be pleased with him), He protected through his people. But the rest were seized by the polytheists, who clad them in coats of iron armour and made them stand in the scorching sun. Every one of them (under the severity of the torment) said what they wanted, except Bilal (may Allah be pleased with him), for he cared nothing for his own life for the sake of Allah, and he had no standing in the eyes of his people either. So they handed Bilal (may Allah be pleased with him) over to the boys, who would drag him around the mountain passes of Makkah, while Bilal (may Allah be pleased with him) kept saying (with his tongue): "Ahad, Ahad" (Allah is One, Allah is One).
This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.

It is narrated from Sayyiduna Jabir (may Allah be pleased with him) that Sayyiduna Umar (may Allah be pleased with him) said: "Abu Bakr (may Allah be pleased with him) is our master, and he freed our master (Bilal)."
This hadith is sahih (authentic), but the two Shaykhs (Bukhari and Muslim) did not record it!