Allusions

Here is Sonnet 29, an interesting choice in that the narrator is frustrated by his life--he feels some kind of lack, until the couplet in which he realizes he wants no other life as long as this "you" is with him.
When in disgrace with fortune and men's eyes,
I all alone beweep my outcast state,
And trouble deaf Heaven with my bootless cries,
And look upon myself, and curse my fate,
Wishing me like to one more rich in hope,
Featur'd like him, like him with friends possess'd,
Desiring this man's art, and that man's scope,
With what I most enjoy contented least:
Yet in these thoughts myself almost despising,
Haply I think on thee,--and then my state
(Like to the lark at break of day arising
From sullen earth) sings hymns at heaven's gate;
For thy sweet love remember'd such wealth brings
That then I scorn to change my state with kings'.

And here is Yeats's poem "The Second Coming"
Turning and turning in the widening gyre
The falcon cannot hear the falconer;
Things fall apart; the centre cannot hold; (HENCE the title of the Achebe novel)
Mere anarchy is loosed upon the world,
The blood-dimmed tide is loosed, and everywhere
The ceremony of innocence is drowned;
The best lack all convictions, while the worst
Are full of passionate intensity.

Surely some revelation is at hand;
Surely the Second Coming is at hand.
The Second Coming!
Hardly are those words out
When a vast image out of Spiritus Mundi
Troubles my sight: somewhere in sands of the desert
A shape with lion body and the head of a man,
A gaze blank and pitiless as the sun,
Is moving its slow thighs, while all about it
Reel shadows of the indignant desert birds.
The darkness drops again; but now I know
That twenty centuries of stony sleep
Were vexed to nightmare by a rocking cradle,
And what rough beast, its hour come round at last,
Slouches towards Bethlehem to be born?