This limb might be described as the "Golden Rule": Do unto others as you would have them do unto you. Yama focuses on ethical principles and integrity, and states that yogis should live their lives nonviolently and truthfully; should exercise self-control; and should not covet, steal or hoard.
This limb is more self-reflective than the first, focusing on religion, spirituality and personal care. It states that a yogi should work toward cleanliness, contentment, spiritual purification, and knowledge about and devotion to God. This limb encourages having good hygiene, regularly praying and attending church services, studying religious scriptures, and establishing a personal meditation practice.
This is the limb that most modern-day yoga students know the best: the physical practice of moving the body into asanas, or postures. Asana is important because it can keep the body strong and flexible, but also because it helps yogis develop concentration and discipline skills necessary for deeper meditations.
Along with asana, pranayama is often practiced during modern yoga classes, as well. It's the process of breathing -- or, more specifically, having control over one's breath. Pranayama means "life force extension," which reflects the belief that proper deep breathing can invigorate and even extend life. Pranayama breathing can be done along with asanas, or it can be done on its own.
Known as the withdrawal of the senses, pratyahara is the practice of turning off the outside world – and the senses of smell, sound, touch, taste and sight -- in order to withdraw and focus on ourselves.
Once pratyahara is achieved, one can move into the stage of dharana, or concentration. During this practice, one might focus intensely on one object, sound, or word in the mind, repeating it over and over and thinking about every little detail. This precedes and sets the stage for meditation.
This stage occurs when the intense concentration of dharana becomes mindful awareness without focus. This uninterrupted flow, also considered meditation or contemplation, is characterized by a quiet mind, with few or no thoughts at all. Beginners may find this to be an nearly impossible task, but just the process of quieting the mind can be beneficial.
Patanjalii describes the eighth limb of yoga as a state of ecstasy, achievable only with much practice and mastery of the first seven limbs. It is a type of transcendence, when one becomes aware of his or her connection to God and to all living things.