Sutra 4.18

सदा ज्ञाताश्चित्तवृत्तयस्तत्प्रभोः पुरुषस्यापरिणामित्वात्॥१८॥

sadājñātāḥ citta-vrttayaḥ tat-prabhoḥ puruṣasya-apariṇāmitvāt ॥18॥

sadā=always; jñātāḥ= are known; citta-vrttayaḥ=the modifications of the mind; tat-prabhoḥ=of that Lord; puruṣasya=of the purusha; apariṇāmitvāt=due to changelessness or constancy॥18॥

Aranya

On Account Of The Immutability Of Purusa Who Is Master Of The Mind, The Modifications Of The Mind Are Always Known Or Manifest.

Taimni

The modifications of the mind are always known to its lord on account of the changelessness of the Purusa.

Sw. Satchidananda

Due to Its changelessness, changes in the mind-stuff are always known to the Puruṣa, who is its master.

Bryant

The permutations of the mind are always known to its Lord, the purusha soul, because of the soul’s unchanging nature.