Bhagavad Gita, Chapter 3 verse 38: As fire is covered by smoke, as the mirror by dust, as an embryo is covered by the amnion, so is the intellect covered by desire.
‘The intellect covered by desire.’ These three metaphors illustrate the ways in which desires mask intellect established in pure consciousness of Self.
1) ‘As fire is covered by smoke.’ Desires arise from pure consciousness of the Self and veil it.
2) ‘As a mirror is covered by dust.’ Desires respond to outside stimulus and covers pure consciousness.
3) ‘As an embryo covers the amnion.’ Desire gives life to pure consciousness but also overshadows it.
In all these ways desire veils pure consciousness and keeps the uninvolved nature of the Self involved in activity.