The Kitáb-i-Aqdas
14.He hath exempted from this those who are weak from illness or age ¶10
The exemption of those who are weak due to illness or advanced age from offering the Obligatory Prayers and from fasting is explained in Questions and Answers. Bahá’u’lláh indicates that in “time of ill-health it is not permissible to observe these obligations” (Q and A 93). He defines old age, in this context, as being from seventy (Q and A 74). In answer to a question, Shoghi Effendi has clarified that people who attain the age of seventy are exempt, whether or not they are weak.
Exemption from fasting is also granted to the other specific categories of people listed in the Synopsis and Codification, section IV.B.5. See notes 20, 30 and 31 for additional discussion.
15.God hath granted you leave to prostrate yourselves on any surface that is clean, for We have removed in this regard the limitation that had been laid down in the Book ¶10
The requirements of prayer in previous Dispensations have often included prostration. In the Arabic Bayán the Báb called upon the believers to lay their foreheads on surfaces of crystal when prostrating. Similarly, in Islám, certain restrictions are imposed with regard to the surface on which Muslims are permitted to prostrate. Bahá’u’lláh abrogates such restrictions and simply specifies “any surface that is clean”.
16.Let him that findeth no water for ablution repeat five times the words “In the Name of God, the Most Pure, the Most Pure”, and then proceed to his devotions. ¶10
Ablutions are to be performed by the believer in preparation for the offering of obligatory prayer. They consist of washing the hands and face. If water is unavailable, the