Which lines in this excerpt from act ii of william shakespeare’s romeo and juliet best convey friar laurence’s ideas about the coexistence of good and evil?

friar laurence:
[the grey-eyed morn smiles on the frowning night,
chequering the eastern clouds with streaks of light,]
and flecked darkness like a drunkard reels
from forth day's path and titan's fiery wheels:
[now, ere the sun advance his burning eye,
the day to cheer and night's dank dew to dry, ]
i must up-fill this osier cage of ours
with baleful weeds and precious-juiced flowers.
the earth that's nature's mother is her tomb;
what is her burying grave that is her womb,
and from her womb children of divers kind
we sucking on her natural bosom find,
many for many virtues excellent,
none but for some and yet all different.
[o, mickle is the powerful grace that lies
in herbs, plants, stones, and their true qualities: ]
for nought so vile that on the earth doth live
but to the earth some special good doth give,
nor aught so good but strain'd from that fair use
revolts from true birth, stumbling on abuse:
virtue itself turns vice, being misapplied;
and vice sometimes by action dignified.
[within the infant rind of this small flower
poison hath residence and medicine power: ]
for this, being smelt, with that part cheers each part;
being tasted, slays all senses with the heart.

[the grey-eyed morn smiles on the frowning night,
chequering the eastern clouds with streaks of light,]

[now, ere the sun advance his burning eye,
the day to cheer and night's dank dew to dry, ]

[o, mickle is the powerful grace that lies
in herbs, plants, stones, and their true qualities: ]

[within the infant rind of this small flower
poison hath residence and medicine power: ]