It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said concerning the saying of Allah Almighty "Then indeed Allah is his protector, and Jibril, and the righteous believers" [Surah al-Tahrim: 4]: "The righteous believers means Abu Bakr and Umar (may Allah be pleased with them both)."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 10439