To get a harvest of virtue, intense spiritual practice is needed though no such effort is necessary to contract vices...

The One is the basis of the many.
To recognize this unity,
one needs practice and effort.

For weeds to grow,
no effort is required on our part.
But, if grain is to be harvested,
the field must be ploughed, weeded,
watered, applied manure and fenced.

So also, to get a harvest of virtue
intense spiritual practice is needed,
though no such effort is necessary to contract vices.
Man has to struggle hard
in order to attain the higher stages
of spiritual development.

He has to overcome many hurdles
and put up with many difficulties and disappointments.

from a divine source