Sayyiduna Farwah bin Musayk (may Allah be pleased with him) came to the Prophet (peace and blessings be upon him) and said: O Messenger of Allah, we have some neighbours in Saba who are people of might, kingship and power. So permit me to invite them to Islam, and if they refuse, permit me to fight them with my people and those who obey me. So he (peace and blessings be upon him) gave him permission. Then the Messenger of Allah (peace and blessings be upon him) changed his mind and said: "As for what you mentioned about Saba, first invite them to Islam; if they respond to you, accept it from them and hold back from them; and if they refuse, do not confront them until my order comes to you." He said: O Messenger of Allah, what is Saba, a land or a woman? He (peace and blessings be upon him) said: "Neither a land nor a woman, but a man who had ten tribes. Six of them turned towards Yemen and four towards Sham. The Yemeni tribes are Madhhij, al-Azd, Kindah, Himyar, the Ash'ariyyun, and Anmar." A man said: O Messenger of Allah, what is Anmar? He (peace and blessings be upon him) said: "He is the father of Bajilah and Khath'am. And those who turned towards Sham are four: Lakhm, Judham, Ghassan and Amilah."
Hadith Referenceالمعجم الكبير للطبراني / باب الفاء / 15926