Breathe not the sins of others so long as thou art thyself a sinner — Bahá’u’lláh
O Son of Man! Breathe not the sins of others so long as thou art thyself a sinner. Shouldst thou transgress this command, accursed wouldst thou be, and to this I bear witness.

Bahá’u’lláh

The Hidden Words, Part One (Arabic), No. 27

Bahá’í Reference Library