Re: Sadhana Defined from lectures of His Divine Grace Srila Narayana Maharaja free ebooks from www.BVML.org
Sadhaka --- one who follows a spiritual discipline to achieve a specific goal; especially the practitioner of bhakti yoga
Sadhana ---the method one adopts in order to obtain a specific goal is called sadhana. Without sadhana one cannot obtain sadhya or the goal of one's practice. There are many differant types of sadhana corresponding with various goals.
Those who desire material enjoyment adopt the path of karma as their sadhana. Those who desire liberation adopt the path of jnana as their sadhana. And those who aspire for the eternal loving service of Sri Krsna adopt the path of bhakti as their sadhana. The sadhana of bhakti refers to spiritual practices such as hearing, chanting, and so on. (note)the Vedic scriptures actually have all information for all jivas to achieve their sadhana and to know the sadhya (methods for obtaining those goals)
Sadhya -- the object or goal which is desired by a person and for the attainment of which he undergoes a suitable process. There are many different types of sadhyas, or objects of attainment, and these are generally grouped into four categories: dharma, artha, kama, and moksa. The sadhya-vastu, or object of attainment, for devotees of the Lord is Bhagavat-Priti or love for the Supreme Lord. This is also known as prema. Bhakti or prema, being an eternal function of the Lord's svarupa-sakti, is not produced by anything, yet when the devotee's heart is purified by performing sadhana-bhakti, it becomes fit to receive the manifestation of the Lord's hladini, pleasure-giving potency. At that time Krsna manifests this hladini, potency in the devotee's heart and it becomes known as bhagavat-priti (see-purusartha). just the basic definition for purusartha is 2 pages so if you want more, then please see
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Blessings
CharuKrsnaDasa