Sayyiduna Aktham bin al-Jawn al-Khuza'i (may Allah be pleased with him) narrated that the Messenger of Allah (peace and blessings be upon him) said: "O Aktham bin al-Jawn! Go on expeditions with people other than your own tribe; your character will become good and you will be honoured among your companions. O Aktham bin al-Jawn! The best of companions are four, the best vanguard is of forty men, the best expedition (sariyyah) is of four hundred men, the best army is of four thousand, and an army of twelve thousand will not be defeated due to small numbers. O Aktham bin al-Jawn! Do not be a companion of two hundred."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18482