In the terminology of Islam, duʿāʾ (Arabic: دُعَاء, plural: ʾadʿiyah أدْعِيَة; also transliterated Doowa), literally meaning "invocation", is an act of supplication. The term is derived from an Arabic word meaning to 'call out' or to 'summon', and Muslims regard this as a profound act of worship. The Islamic prophet Muhammad is reported to have said "Dua is the very essence of worship," while one of God's commands expressed through the Quran is for them to call out to Him:
And your Lord says: "Call on Me; I will answer your (Prayer):
— Quran, sura 40 (Ghafir), ayah 60 There is a special emphasis on du'a in Muslim spirituality and early Muslims took great care to record the supplications of Muhammad and transmit them to subsequent generations. These traditions precipitated new genres of literature in which prophetic supplications were gathered together in single volumes that were memorized and taught. Collections such as Al-Nawawi's Kitab al-adhkar and Shams al-Din al-Jazari's al-Hisn al-Hasin exemplify this literary trend and gained significant currency among Muslim devotees keen to learn how Muhammad supplicated to God.
However, Du'a literature is not restricted to prophetic supplications; many later Muslim scholars and sages composed their own supplications, often in elaborate rhyming prose that would be recited by their disciples. Popular du'as would include Muhammad al-Jazuli's Dala'il al-Khayrat, which at its peak spread throughout the Muslim world, and Abul Hasan ash-Shadhili's Hizb al-Bahr which also had widespread appeal. Du'a literature reaches its most lyrical form in the Munajat, or 'whispered intimate prayers' such as those of Ibn 'Ata Allah. Among the Shia schools, the Al-Sahifa al-Sajjadiyya records du'as attributed to Ali and his grandson Ali ibn al-Husayn Zayn al-'Abidin.