classic waka stream

罪もなき人をうけへば忘草
おのが上にぞ生ふといふなる
Roma-ji

Tsumi mo naki hito o ukeeba wasuregusa
ono ga ue ni zo ou to iu naru

English Translation
If one without sin
is made the object of curse,
they say that forget-
grass will upon one’s own self
grow there upon one’s own self.
Meaning
If one lays a curse upon a person without sin, they say that forget-grass will grow upon oneself, and one will be forgotten by others.
Commentary
Episode Thirty-One: "Forget-grass"

A certain man frequented the chamber of a lady of rank in the palace. The lady regarded the man as someone to be detested and said to him, "Very well. Though now you flourish thick as grass, I shall watch to see what becomes of you hereafter," meaning that although he now prospers greatly, she would look on with pleasure at his eventual downfall.

The poem was composed by the man in response to the lady’s words. It is an exchange of bitter remarks.

In the Ise Monogatari Chokukai, a poem by Ishigami no Otomaro in the Zoku Manyo Collection, Book Eight, beginning "How painful it is to be forgotten—if life remains, well then, I shall become but a blade of grass and watch," is cited as the original poem.
Source
Ise Monogatari
Other