Yoga and Good Conduct in Rigveda
Yoga and good conduct are interdependent, according to Rigveda.
An aspirant has to have good behaviour. Vaisvamitra says:
उत ब्रुवन्तु नो निदो निरन्यतश्चिदारत | (1.004.5.1)
And by calling oneself guardian (ब्रुवन्तु) (of one’s body), not censuring anyone (नो निदो), keeping aloof, attain to gentle intellect (निरन्यतश्चिदारत). Thus, the objective is to develop a kindly or gentle temperament. For this, the advice is to keep aloof, avoid criticising others, and treating one’s own body as a guardian.
Then the sage adds:
दधाना इन्द्र इद्दुवः || (1.004.5)
Give this as an offering to Indra.
Thus, righteous behaviour is not enough. It must be offered to the gods to make man fit for yoga.
On the other hand, yoga itself has the ability to uproot bad tendencies. Thus, sage Kaanva says:
यो अग्निं देववीतये हविष्माँ आविवासति | तस्मै पावक मृळय || (1.012.9)
Yoga through Agni (यो अग्निं) to fit to be worshipped Visnu (देववीतये) offered as oblation (हविष्माँ), uproots as it were evil (आविवासति). Therefore (तस्मै) the good conduct (पावक) and compassion (मृळय) (of the yogi) (तस्मै पावक मृळय. Thus, by offering the fruits of yoga through Agni to Visnu (veetaya), eradicates evil tendencies. That is why we find good conduct and compassion in yogis, says the sage.
 उत ब्रुव – अन्तु नो निदो निर् – अन्यत् – अश् – चित् – आरत |
And (उत) calling oneself guardian (ब्रुव-अन्तु) not (नो) censuring (निद = निदो) free from another (निर्-अन्यत्) attain to (अश्) intellect (चित्) gentle (आरत)
 दध – अना इन्द्र इद् – दुवः ||
Give this (दध-अना = दधाना) Indra (इन्द्र) an offering/honour (इद्-दुवस् = इद्दुवः)
 यो अग्निं देव – वीतये हविष्माँ आव – इव – असति | तस्मै पावक मृळय ||
Yoga (यः = यो) Agni (अग्निं) fit to be worshipped (देव) Veetaya (Visnu) (वीतयः = वीतये) offering an oblation (हविष्मत् = हविष्माँ) uprooted (आव = आव्) as it were (इव) evil (असत् = असति) | Therefore (तस्मै = तस्मात्) good conduct (पावक) compassion (मृडय = मृळय)