Bhashya
यदा वै करोति ।कृतिः इन्द्रियसंयमः चित्तैकाग्रताकरणंच ।सत्यां हि तस्यां निष्ठादीनि यथोक्तानि भवन्ति विज्ञा-नावसानानि ॥
In plain words
When one truly practices—and practice means mastering the senses and focusing the mind—then, and only then, do the stages of commitment unfold as described, culminating in direct realization.
Close to the Sanskrit
When indeed one performs action; action is the control of the senses and the making of one-pointedness of the mind. Because when that is present, the stages beginning with commitment, as described, manifest, culminating in direct realization.