In Jainism, the concept of "lock and key" is metaphorically associated with the Samayik Sutra and the Pratikraman Sutra, particularly within the context of the "Samayik" ritual. The phrase is not explicitly called "lock and key" in Jain scriptures, but its principle is taught as:

• Samayik Sutra acts as the "lock" (talā), symbolically "locking" the devotee from all sinful activities and worldly passions during the period of meditation or Samayik.
• The Pratikraman Sutra acts as the "key" (chābī), "unlocking" or freeing the devotee from the discipline of Samayik when the period ends.

This analogy is often taught by Jain teachers to explain the importance of reciting the proper sutras when beginning and completing the Samayik ritual.

So, in summary:

• Samayik Sutra = Lock
• Pratikraman Sutra (Samayik Uvasaggaharam or Samayik Vachan) = Key

This ensures that the vows taken during Samayik are properly commenced and concluded, maintaining spiritual discipline as per Jain tradition.