Al Quddus – The Holy

He who is free from all error, absentmindedness, is free from incapability and from any kind of defect.
“ Whatever is in the heavens and on earth, doth de- clare the Praises and Glory of Allah; the Sovereign, THE HOLY ONE, the Exalted in Might, the Wise”
(62:1) The Holy Quran
From the root
q-d-s  with the 
classical Arabic
to be pure, clean,
to be far removed
from impurity or
to be holy,
Allah is pure, spotless, without blemish or fault.
Allah is far from, and untouched by, worldly imperfections or faults.
His essence and attributes are of unimaginable purity and perfection.
He is beyond all human understanding of purity, perfection and holiness.
Al-Qudds is the One Who is above need and Whose Attributes are above being deficient.
He is the One Who purifies the souls against sinning,

Quran tells us: The Holy Quran (59:23)