Yoga is both inner and outer work.
Practicing Yamas teach you to see, and honor, your connection with, and to, all of existence. Niyamas teach you how to be responsible for caring for your individual expression in the world. Asanas teach you how to care for, heal, and preserve your physical vessel. Pranayamas teach you how to maximize and channel your precious life force energy. Pratyaharas teach you how to come into greater control of your mind by purifying your senses from attachment to both mental and physical form. Practicing Dharanas teach you how to focus your powers of concentration, thus strengthening your ability to understand and properly apply knowledge. Dhyanas teach you how to deepen your connection to your Highest Truth through meditation and direct experience. And all limbs, mastered one after the other, and simultaneously, are intended to get you to Samadhi, which gifts you with the knowledge of, and connection to, your True Self, nature, and source.
In all eight limbs of Yoga, you learn the true meaning of mind over matter. You see how controlling your senses and desires is only a result of gaining control of your mind, as is controlling your breath, releasing tension from your body, accomplishing your goals, building effective relationships, and truly coming to know your Self.
Through this process of introspection, and the applied force of intention and practice, you come to learn about your innate potential and how to effectively guide and channel it in the world. You learn to understand that all things are connected and see how they are connected and can then work your way back into the full presence of who you truly are by starting with understanding the state of your physical form.
In order to effectively do this, you must move from contemplating the very tangible to the most subtle aspects of yourself (since Yoga is experiential and requires that you study deeply only one thing: yourself). In this way, when you practice Samadhi, after preparing yourself to do so through the limbs practiced before it, you work from the known to the unknown and eventually to the ever-present Truth of who you are as an individual while simultaneously finding your connection to all things in the process.
By contemplating form, then concept, then state of being, then presence, you come to know all that there is to be known in your lifetime and see/understand how you fit beautifully into it.
And, when you fully know yourself through this practice of Yoga, you not only bring freedom and understanding to your personal being, but you also bring liberation, comfort, and knowledge to others through your work and presence as well.