I flipped over to YS 1.33 and looked up the different commentaries.
Maitri karuna mudito peksanam sukha dukha punya apunya visayanam bhavanatas citta prasadanam
From the Jivamukti Yoga Chant Book: To preserve the innate serenity of the mind, a yogin should be happy for those who are happy, be compassionate towards those who are unhappy, be delighted for those who are virtuous, and be indifferent towards the wicked.
From The Textbook of Yoga Psychology by Ramamurti S. Mishra, M.D.: The mind becomes calm and tranquil by cultivating an attitude of friendliness and fellowship toward happy-going persons, compassion and kindness toward the miserable, entertainment and joy toward the virtuous, and indifference toward those who appear to be doing evil.
From The Yoga Sutras of Patanjali Commentary by Sri Swami Satchidananda: By cultivating attitudes of friendliness toward the happy, compassion for the unhappy, delight in the virtuous and disregard toward the wicked, the mind-stuff retains its undisturbed calmness.
This is a meaningful sutra to me in many ways. On one hand, it was one of the sutras that called out to me because of its simplicity and practicality. On the other hand, this was the sutra that I chose for my very first dharma talk. It will forever be associated with that time that I understood and experienced what satsang (attachment to truth; good company) is about. As nervous as I was starting that talk, looking at my fellow Jivamukti TTs made me realize they all wanted me to do well, and I was able to push past my fear and the talk went better than I could have hoped for.
In Sri Swami Satchidananda's commentary, he likened these 4 guidelines to 4 keys to locks that govern all relationships in the world- how to deal with those who are happy, those who are unhappy, those who are virtuous, and those who are wicked. What I love about the way he teaches is that he uses analogies to explain philosophies that may otherwise feel too rigid or conceptual. He breaks down the ideas into simple terms without losing the depth of the teachings, and is thus, a perfect companion reading to the more scholarly commentaries of the sutras.
The Yoga Sutras of Patanjali: Commentary by Sri Swami Satchidananda is available in paperback at Fully Booked (about PHP1150) or in e-Book format at Amazon.com ($11.99).