In Christian theology, like in all religious sciences, the question of human nature is unavoidable. In this article, we shall consider the problem with a special overview of its place in ascetic practices. As a necessary part of the orthodox Christian life - purification, enlightenment and theosis - we shall dedicate special attention to the question of conscience, which has a lot of significance for determining the meaning of spiritual life in terms of theological theory. As a consequence of neglecting of personal spiritual life, a vast majority of theologians develop a false understanding that ascetic practice of the struggle with bodily passions is similar to neoplatonic negative relationship to the body itself. Because of that in this article we try to consider explanations of the terms passion and world in the works of Isaac the Syrian. In irfan we also find a number of parallels in terms of the already mentioned questions.