Bhagavad Gita 3.38

धूमेनाव्र्यते वह्निर्यथादर्शो मलेन च |
यथोलबेनावृतो गर्भस्तथा तेनेदमावृतम्

Translation

Just as a fire is covered by smoke, a mirror is masked by dust, and an embryo is concealed by the womb, similarly one’s knowledge gets shrouded by desire.