The phrase "Nimitta sada nirdosh" is a common saying in Jain philosophy and is often quoted in Jain literature, especially in the context of karma theory and spiritual conduct.

Meaning:

• "Nimitta" means an external agency, instrument, or cause.
• "Sada nirdosh" means "always innocent" or "always faultless".

Interpretation: The phrase means that the external agencies (nimitta) that appear to be the cause of our pleasure or pain are always innocent; the real cause is our own karma. Therefore, we should not blame others for our suffering or happiness.

Source: This phrase is not directly from ancient Sanskrit scriptures like Agamas or Sutras, but it is rooted deeply in Jain philosophical literature, particularly in the commentaries and explanations by Jain Acharyas (monks and scholars) in Prakrit, Gujarati, Hindi, and other vernacular Jain texts. It is often found in the teachings and discourses of modern Jain saints, especially in the Shwetambar Terapanthi sect, and is widely used among followers of Acharya Mahapragya and Acharya Tulsi.

Summary:

• It is not a direct Sanskrit scriptural quote, but is derived from the essence of Jain karma philosophy.
• Widely used in Jain literature, discourses, and teachings in Prakrit, Gujarati, Hindi, etc.
• Explains that external causes are not to be blamed—our own karma is responsible for our experiences.

References in Jain literature:

• "Nimitt nirdosh chhe" is widely discussed in Jain Pravachans and books on Jain karma theory.
• Acharya Mahapragya and other Jain scholars have extensively explained this concept.

If you want a direct scriptural reference, you may not find this exact phrase in ancient Sanskrit Agamas, but the concept is thoroughly embedded in Jain karma doctrine.