Satsang is very much necessary
to attain God as Lord Narada says in Bhaktisoothra.
Narada says"Bhakti,the
experience of God comes through Satsang. The fruits that one receive from
Satsang will never go waste.
Like when one who sits near
a garland or flower gets the smell of it similarly in the 'Sangham' of Sadhus
the sacred 'smell' of Bhakti will overflow. That will purify the mind.
The mind of a true Bhaktan
when he/she in the "Dusangha" (people with bad qualities) will be
similar to the state of fish taken out of water.It doesn’t have an existence.
The relief it gets when back in water is similar to the case when
bhaktan/devotee back to Satsang.
Satsang doesn’t just mean
listening to talks or talk between people;smriti or remembrance of God itself
is Satsang. In Meditation or Dhyana of the God the mind gets involved (sanga)
with the reality or truth(satva ).