From Institutes of Manu.

The soul itself its awful witness is.
Say not in evil doing, 'No one sees,'
And so offend the conscious One within,
Whose ear can hear the silences of sin.

Ere they find voice, whose eyes unsleeping see
The secret motions of iniquity.
Nor in thy folly say, 'I am alone.'
For, seated in thy heart, as on a throne,
The ancient Judge and Witness liveth still,
To note thy act and thought; and as thy ill
Or good goes from thee, far beyond thy reach,
The solemn Doomsman's seal is set on each.