Bahá’u’lláh confirms an injunction contained in the Bayán which makes it unlawful to carry arms, unless it is necessary to do so. With regard to circumstances under which the bearing of arms might be "essential" for an individual, ‘Abdu’l-Bahá gives permission to a believer for self-protection in a dangerous environment. Shoghi Effendi in a letter written on his behalf has also indicated that, in an emergency, when there is no legal force at hand to appeal to, a Bahá’í is justified in defending his life. There are a number of other situations in which weapons are needed and can be legitimately used; for instance, in countries where people hunt for their food and clothing, and in such sports as archery, marksmanship, and fencing. On the societal level, the principle of collective security enunciated by Bahá’u’lláh (see Gleanings from the Writings of Bahá’u’lláh, CXVII) and elaborated by Shoghi Effendi (see the Guardian’s letters in The World Order of Bahá’u’lláh) does not presuppose the abolition of the use of force, but prescribes "a system in which Force is made the servant of Justice", and which provides for the existence of an international peace-keeping force that "will safeguard the organic unity of the whole commonwealth". In the Tablet of Bis̱ẖárát, Bahá’u’lláh expresses the hope that "weapons of war throughout the world may be converted into instruments of reconstruction and that strife and conflict may be removed from the midst of men". In another Tablet Bahá’u’lláh stresses the importance of fellowship with the followers of all religions; He also states that "the law of holy war hath been blotted out from the Book". 174. and permitted you to attire yourselves in silk #159 According to Islamic practice, the wearing of silk by men was generally forbidden, except in times of holy war. This prohibition, which was not based on the verses of the Qur’án, was abrogated by the Báb. 175. The Lord hath relieved you ... of the restrictions that formerly applied to clothing and to the trim of the beard. #159 Many rules about dress had their origins in the laws and traditional practices of the world’s religions. For example, the S̱ẖí’ih clergy adopted for themselves a distinctive headdress and robes and, at one time, forbade the people to adopt European attire. Muslim practice, in its desire to emulate the custom of the Prophet, also introduced a number of restrictions with regard to the trim of the moustache and the length of the beard. Bahá’u’lláh removed such limitations on one’s apparel and beard. He leaves such matters to the "discretion" of the individual, and at the same time calls upon the believers not to transgress the bounds of propriety and to exercise moderation in all that pertains to dress. 176. O Land of Káf and Rá! #164 Káf and Rá are the first two consonants of Kirmán, the name of a city and province of Iran. 177. We perceive that which secretly and stealthily diffuseth from thee. #164