How Can One Attain Purity

Since man is made of clay, he can never be completely pure.
Since clay is basically foul, how can humans escape their basic nature?
Purity does not lie in rituals, nor can human nature be changed by effort.
Those who love God and remain conscious only of their Beloved attain purity.

Syed Ali Bin Usman Al-Hujwiri [may Allah be pleased with him], "Kashf al-Mahjub"