In Romeo and Juliet, what is the opposition mentioned in Friar Lawrence's speech when we first meet him?

There are two elements of opposition that we can identify
in this excellent speech that introduces us to Friar Lawrence in Act II scene 3 of this
excellent tragedy. His speech starts off by describing dawn in opposition to night. Note
how dawn is presented:

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The grey-eyed morn smiles on the frowning
night,

Check'ring the eastern clouds with streaks of
light;

And flecked darkness like a drunkard
reels

From forth day's path and Titan's burning
wheels.

There is a clear
opposition between dawn and night. Dawn is personified as "smiling" with its grey eyes,
whereas night is "frowning" and "flecked," being compared to drunkard staggering out of
dawn's path and the sun.

However, note too the second, and
perhaps more profound and significant opposition that is created between how Friar
Lawrence characterises night negatively and Romeo in the preceeding scene characterises
it positively. Romeo says, in Act II scene 2, that night is
"blessed":

O
blessed, blessed night! I am afeard,

Being in night, all
this is but a dream,

Too flattering-sweet to be
substantial.

Thus there
exists a second, deeper and more significant opposition between the way that night is
viewed by these two characters, that could be argued to foreshadow the tragedy
ahead.