Who were the thousand men whom Umar ibn al-Khaṭṭāb sent to Amr ibn al-Āṣ?

Many Companions (may Allah be pleased with them) were considered equal to a thousand men due to the strength of their faith, their courage, and their sincerity. Among them were Az-Zubayr ibn Al-Awwam, Al-Miqdad ibn Al-Aswad, Ubadah ibn As-Samit, and Maslamah ibn Mukhallad. These were among those whom Umar sent to Amr ibn Al-Aas as reinforcements for the conquest of Egypt, and he wrote to him: "I have reinforced you with four thousand men, each thousand of whom are equivalent to a thousand." Among them also were Kharijah ibn Hudhafah and Talhah ibn Khuwaylid Al-Asadi, as it was said that each of them was equivalent to a thousand horsemen.