Mīmāmsa Sūtra 01.01.03

तस्य निमित्तपरीष्टिः ॥३॥

tasya nimittaparīṣṭiḥ ॥3॥

[तस्य (tasya) - of him; of that; निमित्त (nimitta) - cause; sign; omen; परीष्टिः (parīṣṭiḥ) - examination; investigation; inquiry;]

(Of him, the examination of cause. )

Its (Dharma's) cause must be investigated.