During the final days of the Prophet Muhammad, two Arabs, Musaylema ibn Hubayb of Yamama and Aswad ibn Kaab Ansi of Sana’a claimed Prophethood. Musaylema sent a letter to the Prophet in 10 A.H. which read: “From Musaylema, messenger of Allah to Muhammad, messenger of God, peace be upon you. Later on, there should be no doubt about it that I have been associated with you in the matter of prophethood. Hence half the land belongs to me and half to the Quraysh.” Two messengers called Ibn an-Nuwana and Ibn Usal, brought his letter to Madinah. The narrator of this incident has this to say:
“When the messengers of Musaylema Kazzab, brought this letter, I heard the Prophet ask: ‘Do you also believe what Musaylema has to say?’ They replied in the affirmative. Then the Prophet said, “By God, if it were not the custom that the messengers should not be killed, I would have had you beheaded.’”
The narrator, Abdullah ibn Mas’ud explained that after this incident a sunnah (custom) was established that messengers were not to be killed (Al-Bidayah wa-an-Nihayah, Vol. 5, pp. 51-52).
This sunnah of the Prophet tells us of a very important principle of Islam, namely, that international matters will be dealt with according to international customs. In every age, certain traditions are observed in matters of international relations. In modern times too there are many such customs to which the United Nations has now given a more organized form.
All such customs and traditions should be held in the same respect as in non-Muslim countries. However, if any prevalent custom is clearly illegal, in terms of Islam, for instance, the offering of alcoholic drinks at international meetings, then that part of the custom is not to be observed.