In yoga tradition a code of social and personal human behavior is called YAMA and NIYAMA rules. In Patañjali's Yoga Sūtras YAMA and NIYAMA are the first two stages on yoga way. Some commentators interpret literally such sequence of actions and say that the main condition for a person willing to start his own pathway to personal evolution and self-improvement is observance of these rules. The main argument to the favor of such position is that the practice enhances the energy status and performance of a human, thus, amplifying and demonstrating more vividly all qualities present, as positive so negative. Observance of yama and niyama rules, generally speaking, ethical standards in yoga tradition, serves to insurance of a person on his way of spiritual development against movement towards "wrong direction".
In return, the commentators of Svātmārāma's Hatha Yoga Pradīpikā point out that it may be too questionable for a modern person to be in a direct conflict with his mind at the very beginning of his spiritual search. That is why the traditions of Hatha yoga practice start with body cleaning-up, then there are asana and pranayama, and yama with niyama may be practiced later, when the mind is more stable. There is no and can't be the only veracious interpretation, as it shouldn't be forgotten that every person starts his own way from a certain starting point, conditioned by a lot of factors and peculiarities of his life, as well as the surrounding reality.
Due to this it's important to understand that any division and separation of individual stages and sequences of limbs in yoga is caused by a necessity of conceptual understanding of the Tradition essence. It is no mere chance that in Patañjali's Yoga Sūtras there is dhāraṇā first (subject concentration), and only then dhyāna (coping with duality, adunation with subject). In order to refuse from a name and limitations of concepts it's necessary to understand and study them thoroughly. Applicably to the present article topic it may be said that it's necessary at first to examine and, at least, try to observe rules of Yama and Niyama, while practicing yoga. According to Desikachar, "Notwithstanding where we start yoga – from asana, pranayama, meditation or Yoga Sūtras studying", - the essence of studying process is the same. The more we progress, the more we realize the integral nature of our being, understanding that we consist of a body, breath, mind and something else". Everything influences everything, transformations are initialized by yogi gymnastic practice, cleaning-up of a body and energetic human structures, it also influences on a process of ethics transformation from outside into the internal component of a human.
Let's get in Yama and Niyama notions.