Ungrateful are those on this earthly road, Who do complain that life is made of tears, That happiness on earth one cannot find, That we are made of sorrows and of fears.

...blessed be the heart who finds its way to the eternal summer. [...to the realisation of eternal gratitude that things aren't worse, because they always can be!]

That which is lacking in the present world is a profound knowledge of the nature of things.

...Blessed be the heart who finds its way to the eternal summer. - where grateful happiness is found through understanding that whatever your situation is, it could always be worse, but isn't... and the thought that things could always be better and the bitter unhappiness this creates is discarded!