स तु दीर्घकालनैरन्तर्यसत्कारासेवितो दृढभूमिः ।sa tu dīrgha-kāla-nairantarya-satkārāsevito dṛḍha-bhūmiḥAnd that [practice] attains firm ground when cultivated for a long time, without interruption, and with devotion. Yogasūtra 1.14
