All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
The recitation of the Quran by heart (from one’s memory) without touching it does not need ablution, but it is an obligation on the one who touches it to perform ablution. Allah Says (what means): {In a Register well-protected; None touch it except the purified.} [Quran 56:78-79]
The purification referred to in this verse encompasses the purification from both ritual impurities; i.e., major impurity and minor impurity as well. The Prophet wrote a letter to the people of Yemen in which he mentioned “No one should touch the Quran except being in the state of ritual purity.” [Athram and Ad-Daaraqutni]
Imam Maalik narrated it as a Mursal Hadeeth.
Allah knows best.