Asteya is the third Yama of yoga and translates to non-stealing.
Sounds like an easy one to tick off the list, but it isn't just refraining from taking things and not physically stealing from others. It represents so much more at the suble and mental level, such as not stealing energy, knowledge or credit from others as well.
It encompasses this acknowledgment and consciousness that we do not steal opportunities from people or accept privileges without a proper energy exchange for them. Feelings like jealousy, being over-protective, preventing the learning, growing and confidence in others are all examples of why we should practise this yama.
Non stealing is especially important for spiritual hierachy. For taking spiritual teachings or advantages from others without paying something back in appropriate forms (such as paying it forward or trying to live by their teachings) is considered theft.
Ravi Ravindra quotes Krishna in the Bhagavad Gita in his Yoga Sutras translations, as he says: "Foster the gods with yajna (sacrifice, sacred exchange of energy between levels) as they foster you; by nourishing each other, you will attain the supreme good. Fostered by yajna, the gods will bestow on you the joys you cherish. Those who enjoy the gift of the gods without giving to them in return are verily thieves (3:10-12)."
Again, we usually need stillness and reflection to draw awareness to our behaviours to discern whether or not we are engaging in these practices. When we ask ourselves the questions in a quiet place, we can usually find the answers for ourselves.