|Chapter 3: Karma-yoga|
yajnarthat karmano 'nyatra
loko 'yam karma-bandhanah
tad-artham karma kaunteya
Work done as a sacrifice for Vishnu has to be performed, otherwise work causes bondage in this material world. Therefore, O son of Kunti, perform your prescribed duties for His satisfaction, and in that way you will always remain free from bondage.
In the last verse (3.8) Krishna had emphasized on the importance of karma of work with knowledge or "niskama karma yoga." This allows for a soul to be active, but in a detached way, so that he is protected from material entanglements. Now He further elaborates on "what kind of work?" Krishna began with stressing on the importance of performing prescribed duties. Arjuna may comment that even this kind of work would results in reactions and thus bind him to their consequences. In response to this implicit query, Krishna elevates Arjuna to the next level of consciousness – that of pure devotional service, which is attained by working for Vishnu or Krishna. Externally there is no difference between a person performing his prescribed duties and another person performing his prescribed duties for the satisfaction of Krishna. The difference is in the consciousness. The former may be attached to the fruits of the activity, detached from the fruits of the activity or detached from the activity itself on the strength of knowledge. The later does every thing as an offering to Krishna, so the detachment is implicit. This is a key verse since Krishna introduces the concept of the daivi-varnashrama as opposed to karma or gyana varnashrama. In karma or gyana varnashrama the prescribed duties are performed for the sake of pious enjoyment (karma) or detachment (gyana) – but in daivi varnashrama they are performed for the satisfaction of the Supreme Lord. While the other two processes offer a step by step gradual elevation towards the ultimate goal of bhakti – in daivi varnashrama, bhakti becomes an essential ingredient from the very initial stage. This process of gradual elevation in consciousness is a cause of considerable confusion amongst casual readers of the Bhagavad-gita. When Krishna talks about a particular stage towards bhakti, people often interpret it as an alternative to bhakti. In the next seven verses (3.10-3.16) Krishna explicitly lays out what is commonly known as the "yoga ladder," or the various stages of consciousness that leads one to the ultimate platform of bhakti.
Please read the Sanskrit Verse and the Prabhupada's Purport.