Prayer is used to express an individual's love of God and to affect their inner self. Prayer can also be used to obtain specific material ends, but the Baháʼí writings state that it is more important to pray for the love of God without any other hope or fear. Baháʼu'lláh wrote that prayer is essential to any undertaking, and that it attracts confirmations from God. The Baháʼí teachings state that individual prayer should be performed when one is alone, and when free of distractions such as early in the morning or late at night. Collective prayers, which usually are performed by individuals taking turns in reading prayers, are also encouraged; collective prayers are usually performed at the beginning of meetings such as Nineteen Day Feasts, and Baháʼí administrative meetings. Shoghi Effendi, the head of the Baháʼí Faith in the first half of the 20th century, wrote that prayers may be addressed to God, Baháʼu'lláh, or other Manifestations of God; he recommended, however, that the prayers be either directly or indirectly addressed to Baháʼu'lláh. Obligatory Baháʼí prayers In addition to general prayers, Baháʼu'lláh prescribed a daily obligatory prayer in his book of laws, the Kitáb-i-Aqdas. The obligatory prayer is a primary religious obligation starting at the age of fifteen and it is the most important kind of prayer. The purpose of the obligatory prayer is to foster the development of humility and devotion. Unlike almost all other prayers in the Baháʼí Faith, there are specific regulations concerning the obligatory prayers; however, obligatory prayer is a personal spiritual obligation and thus, no Baháʼí administrative sanction can be obtained if a Baháʼí fails to say his prayer daily. Baháʼu'lláh wrote three obligatory prayers — the short, the medium and the long — and Baháʼís are free to choose to say one of the three each day. The short and the medium prayer have to be said at specific times; the short has to be said once between noon and sunset and the medium has to be said three times daily: once between sunrise and noon, once between noon and sunset and once between sunset and two hours after sunset. The long prayer can be said at any time in the day. The medium and long prayers also include movements and gestures during the prayers, which are themselves obligatory except when a person is physically incapable of performing them. Shoghi Effendi has written that