Brahma Bindu Upanishad is one of the minor Upanishads and is similar to Amrita Bindu Upanishad.
(Mind) moved by lust is impure; free of lust it is pure.
Cows are many-colored; the milk (of all) has but one color.
Like ghee remaining hidden within milk (which is brought out by churning it with a churn), the knowledge (of the self) is remaining hidden within every being. That should be attained only through the process of churning with the mind as the churn.
The wise one, keen in the knowledge and experience rather than the book reading, should, after such reading get rid of such books and reading like the one who, interested only in the grains thrashing the crop and getting rid of the crop to retain only the grain.
Brahma Bindu Upanishad