Countee Cullen - From the Dark Tower

We shall not always plant while others reap
The golden increment of bursting fruit,
Not always countenance, abject and mute,
That lesser men should hold their brothers cheap;
Not everlastingly while others sleep
Shall we beguile their limbs with mellow flute,
Not always bend to some more subtle brute;
We were not made to eternally weep.
The night whose sable breast relieves the stark,
White stars is no less lovely being dark,
And there are buds that cannot bloom at all
In light, but crumple, piteous, and fall;
So in the dark we hide the heart that bleeds,
And wait, and tend our agonizing seeds.

Countee Cullen

http://www.poemhunter.com/poem/from-the-dark-tower/