The two slokas (verses) that we chant to invoke Lord Patanjali begin the Bhojavritti, Bhoj’s commentary on the Yoga Sutras. It says, first of all, that Lord Patanjali is considered to be the incarnation of Adhishesha, the cobra, which is the seat for the Lord Vishnu, the very creator of this world. It is said he took birth three different times, giving three different sciences for people to improve themselves. The first is yoga.
yogena cittasya padena vacam
To purify the mind (citta), purify the consciousness, Patanjali gave the science of yoga (yogena) to us. To purify our use of words (pada) and speech (vacca), he gave a commentary on grammar to us, so that our use of words and way of
speaking is clarified, distinct and pure.
malam sarirasya ca vaidyakena
To remove the impurities (malam) of the body (sarira), he gave us the science of medicine (vaidyakena).
yopakarottam pravaram muninam
Let me go near the one who has given these things