A hafiz is a person who has memorised the entire Quran and can recite it from memory, and the title is at once a term of respect and one of the most valued attainments in Muslim life.
The whole book by heart
To be a hafiz is to hold the complete text of the Quran in memory, able to recite any part of it accurately, an achievement requiring years of disciplined study, usually begun in childhood, and it is honoured as the living preservation of the revelation in the heart of the believer, a form of guarding the text that runs alongside the written copies. The word means guardian, and the hafiz is understood as one who guards the Quran by carrying it within.
Preservation across the generations
The memorisation of the whole Quran by many people in every generation has been, from the beginning, one of the principal means by which the exact text has been preserved and transmitted, so the office of the hafiz is not merely personal devotion but part of the mechanism by which the community keeps the revelation intact and identical across time and place. The hafiz is called upon to lead prayers, especially the long night prayers of Ramadan in which much of the Quran is recited, and the attainment carries high honour in the community. There is no ordination; the title is earned by the feat of memory and the fidelity of the recitation, and the completion of memorisation is often marked by celebration in the family and the community.