(Kadamba Kanana Swami, 2008, Amsterdam, Netherlands, Lecture)
Austerity in itself is not a limb of bhakti. Bhakti has sixty-four limbs; this means that there are sixty-four types of activities which give us bhakti but austerity is not amongst them.
However, austerity is glorified in the scripture that by performing sacrifice, by giving in charity and by engaging in austerity even saintly men are being purified. So in this sense, austerity is held in high esteem in the scripture. It is also said, nayam deho deha-bhajam nrloke, kastan kaman arhate vid-bhujam ye, tapo divyam putraka yena sattvam, suddhyed yasmad brahma-saukhyam tv anantam (Srimad Bhagavatam 5.5.1). This is where Maharaj Rsabhadeva is speaking to his one hundred sons and instructing them about spiritual life. He says that this human form of life is not meant for sense gratification; this human form of life is meant for penances and austerities so that one may reach the transcendental state of happiness which is beyond the three modes of material nature.
Like this, austerity is glorified in the scripture but austerity is a preliminary – austerity gives us strength to practice bhakti but austerity in itself is not spiritual. A lack of austerity may make us weak in our determination. So a certain amount of austerity is required as a preliminarily activity to get some basic determination because in the initial stages of devotional service we are acting in the mode of goodness; we are not yet transcendental; we are in a transcendental process but we ourselves are not transcendental. Therefore we are trying to fix ourselves in the mode of goodness. This is the interim stage of devotional service. Then, as we get more and more advanced, eventually we will come to a transcendental stage.