Nature's energy now flows abundantly in the sadhaka

Verse 4.3

णनणभत्तभ अप्रमोजकं प्रकृ तीनां वयिब ् दस्ते तत् ऺ ु णत्रकवत े ॥३॥ 

nimittam aprayojakan prakritinan varannabhedastu tatah kshetrikavat

Good deeds, etc., are not the direct causes in the transformation of nature, but they act as breakers of obstacles to the evolutions of nature, as a farmer breaks the obstacles to the course of water, which then runs down by its own nature.

As a farmer builds dykes between fields to regulate the flow of water, evolved yogis channel the abundant flow of nature's energy to free themselves from the bondage of their actions and develop spiritual insight. Even if sadhana fails to bring about complete transformation in the life of a sadhaka, it certainly serves to remove obstacles in the path of his evolution.

Past good actions (karmasaya) indirectly become instrumental in accelerating the flow of natural tendencies for the good of the consciousness. A farmer heaps up banks of earth to collect water and soak part of a field. When one area is soaked, he opens the bank to enable the water to flow into the adjoining area, continuing until the entire field is thoroughly irrigated. 

Then he sows the best seeds to get the best of harvests, and enjoys the fruits.

Through yogic discipline, the yogi removes all obstacles to his evolution, and enjoys emancipation.

Thus disciplined, the yogi's enhanced energy spontaneously removes all

fluctuations and afflictions which hinder his spiritual growth, enabling him to gain insight into his very being, his soul.

This sutra is a beauty in itself. Nature's energy now flows abundantly in the sadhaka. This energy is built up and concentrated through practice of Asana, pranayama and bandha, which can be thought of as 'dykes' in the system to regulate and channel energy, so that mind and intelligence may diffuse evenly throughout one's being.

PATANJALI YOGA SUTRAS