Al-Fatiha ('The Opening') is the first surah of the written Quran and, at seven verses, its most frequently recited passage: it is said in every unit (rak'a) of the five daily prayers. It is a prayer in the worshipper's own voice, praise of God the Merciful, Lord of the Judgement Day, followed by the plea to be kept on 'the straight path.' Tradition calls it Umm al-Kitab, the Mother of the Book, and as-Sab al-Mathani, the seven oft-repeated verses (a title the Quran gives at 15:87). It is used to open undertakings, as a healing recitation, and to seal supplications.
Al-Fatiha is unusual among the surahs in being addressed to God rather than spoken in God's voice, which is why classical commentators call it a conversation: the worshipper praises and petitions, and tradition holds that God answers each phrase in turn, a hadith qudsi preserved by Muslim in which God says "I have divided the prayer between Myself and My servant in two halves" and responds line by line to the reciter. Because it must be recited correctly in every rak'a, the earliest tafsir literature, al-Tabari's commentary among the first, devotes disproportionate space to its seven verses, parsing "Lord of the worlds," "the Compassionate, the Merciful" and "Master of the Day of Judgement" as a compressed statement of God's relation to creation before the plea for guidance even begins. Sufi practice extended its use beyond the ritual prayer: "reciting the Fatiha" for the dead or for a departed teacher became, and remains, a common act of dedication at gravesides and in remembrance gatherings across the Muslim world, functionally comparable to the way the Lord's Prayer or the Kaddish anchor devotion in other traditions without being doctrinally equivalent to either.