The fifth and final yama or "great vow" as taught by Patanjali in the Yoga Sutras is aparigraha. 
 
Broken down into it's sanskrit parts, 
pari means "that which is all around us"
graha means "to grab or to grip"
a is a prefix that negates a word

Put it all back together and Patanjali says, "Don't grab onto everything that is around you (or in a simplified version), don't be greedy!". He goes further by saying that when we are established in non greed, we will come to know the meaning of our lives.

The ancient Indian practice of trapping monkeys is often used to describe this yama.

Long ago in order to catch monkeys, hunters would carve out a coconut leaving a hole just big enough for a monkey's stretched out hand to fit through. Then they would anchor the coconut to the ground. Rice or sweet treats would be placed inside of the coconut as bait. The hungry monkeys would smell the rice and squeeze their hands through the hole and greedily grasp the goodies in their fists. When they tried to pull their hand back out, their tightly closed fist was too big to fit. As they struggled to pull their bounty out of the coconut, the hunters could easily capture them. What the monkeys didn't realize was that it was their own unwillingness to release the grip on their prize that caused their self imposed prison.

They say that "what we possess, possesses us".

Like the monkeys in the self imposed coconut trap, all of the stuff that we greedily aquire begins to weigh us down, and our best attempts to be free while holding onto it just leaves us feeling trapped. 

We aquire and hold onto material possessions, old beliefs and thoughts, grievences of the heart, and identifications with our physical bodies long past their usefullness. 

Its okay and often times necessary to aquire new things. Keep in mind however, that when we aquire new things, new thoughts, new ideas, and new feelings, we must also release or let go of the old ones so that we will have the space to take in what's new.

Giving away money and material possessions to those in need, letting go of grievences through forgiveness, and 
leaving the past in the past, will leave us feeling lighter and may even bring us closer to knowing the true meaning of our lives.

There's a story about two monks walking along a riverbed. They come across a woman crying at the side of the river. She needs to cross to get to her village, but she is too afraid.

The first monk continues past her remembering the vow that he has taken which forbids him from having contact with women.

The second monk picks her up, carries her across the river, sets her down on the other side, and continues silently on his way.

When the two monks meet up hours later, the first monk can barely contain himself. "How could you do that!" he says, "You know that we are forbidden to touch women!" The second monk says, "Brother, I put her down hours ago, it is YOU who still carries her."

Material possessions, worries, concerns, anger, sadness, stories from our past, even excess weight are all things that we can carry around with us. We store our stuff in our homes, our bodies, our minds, and our hearts leaving very little space to be open and present to anything new that might come in.
 
From the wisdom of yoga philosophy, we learn to practice aparigraha, which is translated as non hoarding or greedlessness. The more stuff we collect and/or hoard, the more we will be weighed down or anchored to that stuff which prevents us from being fully present to life as it is now.

There is nothing wrong with having stuff. It is when we hold onto to that stuff after it has passed it's usefullness that it becomes a problem. When we keep books, clothes, furniture, and other items that don't serve a purpose any longer because "we might them need someday", there may be an underlying fear that we are not aware of. 

This fear of not having enough or not having our needs met can drive us to hold onto our stuff like a security blanket. Our sentimental items like greeting cards from a loved who has passed or a nick nack from last year's vacation often can keep us anchored or stuck in the past, and in denial of the truth that we will have to give it all up at some point. 

The stuff that we carry in our minds and hearts may be harder to recognize. We get stuck in a story from our past or a grievance that we can't let go of, and we may not realize the damage that it is doing to us in the present. 

The monk who broke his vow most likely experienced discomfort for his actions, but instead of carrying his pain and keeping it alive in his mind and heart, he chose to set it down like he set the woman down at the side of the river.
 
Although the other monk didn't break his vow, he caused his own suffering by carrying the story in his mind for a long time afterwards.

The practice of yoga encourages us to simplify our lives by leaving behind that which no longer serves a purpose for us. Aparigraha can help us to free up space in our homes,our bodies, our minds, and our hearts and with this spaciousness that we create, the possibilities for something new to enter might even be transformational.