Yoga Sutras of Patanjali
The yoga sutras are based on Sankya philosophy, which is a dualistic philosophy, different to that of non-dual Tantra. This means that unlike Tantra, there are two ultimate and irreducible principles of reality. They are:

1. Purusa– Pure consciousness/ the atman/ the soul/ spirit/true self/ essence nature/boundlessness/existence.

2. Prakriti– material reality. Everything that exists in this manifest world, from your body and mind, to thought, emotions, nature, the universe comes from this principle.

In Patanjala yoga, what causes human suffering is confusing the belief that prakriti (body/mind) reality is part of pursusa/spirit/ consciousness.

Let’s briefly revisit why we as human beings experience suffering. It mainly has to do with the experience of identification, common to all yoga traditions. On a day to day level, most of us identify and understand ourselves to be none other than the mind. We believe we are our thoughts, feelings, emotions and all the roles we play in our life. Our mind has such a tight grip over our experience of ourselves and of reality, that we come to identify ourselves through our mental constructs or states of mind.

The main goal of Patanjali’s system is to bring the mind to a point of stillness that consciousness can clearly see it is completely separate from the mind. In fact Patanjali’s definition of yoga is found in Sutra 1.2

“Yoga is the stilling of the fluctuations of the mind”
In Sutra 1.5, Patanjali states that there are five categories or changing states of mind, which are either detrimental (klista) or non-detrimental (aklista) to the practice of yoga. These are the vrittis. The vrittis are sensual impressions, thoughts, ideas, cognitions, feelings, activity or mental states. The vrittis constantly pull consciousness away from its own pure nature, channeling it into the realm of prakriti/body mind.

These changing states of mind or vritts are extremely detrimental and are caused by the five klesas. The klesas impede not only our yoga practice, but are what fundamentally causes all our suffering. They are:
1. Ignorance
2. Ego
3. Attachment
4. Aversion
5. Clinging to life

These five klesas are considered detrimental because they are viewed as the seeds of karma. Karma refers to any initial action, whether good or bad and all its subsequent reactions that it produces. According to Sankya philosophy, they can ripen in this life time or they can spill over into the next. This cycle of spilling over into the next life time is called samsara.
Karma, or actions that keep us attached to the external world and forgetful off our true nature is generated by the fluctuations in the mind and these fluctuations are caused by the vritts. So the goal here is to learn to:

1. Know our true or essence nature so that we don’t remain ignorant
2. Stop misidentifying our essence nature with our body and mind. We are not our body and mind- ego
3. Learn not to be overly attached to things and learn to let go of things that keep us away from realising our essence-nature. Unhealthy attachments include the stories we have about ourselves and life that keep us stuck and suffering, the thoughts and beliefs we cling to that don’t serve our own wellbeing and the well-being of all of humanity, letting of of relationships and people that have broken our hearts, letting go of our hurt and anger as well as good experiences in life that we hold on to and want more of and finally letting go of all the obsessiveness we have with material wealth- attachment
4. Learning to face the things that we are avoiding because they are too difficult, too hurtful, too scary, or too triggering. It can even be about avoiding getting into healthy, happy relationships because we are fearful of being vulnerable or getting hurt- aversion
5. Being scared to die and not facing the reality or our own impermanence or holding on to a loved one in an unhealthy way after they have died- clinging to life 
As a side note, Patanjali explicitly states that we don’t necessarily have to believe in a Divine reality or God to realise or essence-nature, but he does say that it does fast track our spiritual journey if we do! Another worthy contemplation!

Om Shanti, Shanti, Shanti
Yes Peace, Peace Peace