classic waka stream

かしは木に葉守の神のましけるを
しらでぞ折りしたたりなさるな
Roma-ji

Kashiwagi ni hamori no kami no mashikeru o shirade zo orishi tatari nasaru na

English Translation
I did not know that
the god who guards the leaves was
dwelling in the oak
and so I broke the branch off
May no curse come of it, please
Meaning
I did not know that the god who guards the leaves was dwelling in that oak, and so I broke the branch. May no curse come of it.
Commentary
68 The God Who Guards the Leaves

The lord of the Biwa mansion sent to Toshiko's house, where a kashiwa oak was growing, asking leave to have a branch broken off. She had a branch broken, wrote a poem, and sent it with the branch: "Waga yado o itsuka wa kimi ga narashiba no narashigao ni wa ori ni okosuru". The lord of Biwa's reply was "Kashiwagi ni hamori no kami no mashikeru o shirade zo orishi tatari nasaru na". That is the whole of the section.
The lord of the Biwa mansion is Fujiwara no Nakahira, so called from the residence where he lived. Toshiko was the wife of Fujiwara no Chikane and appears in the sixty-sixth and sixty-seventh sections. The kashiwa oak was held to house the god who guards the leaves.
The setting is the moment after the branch and poem reached him.
What prompted his poem is hers, "Waga yado o itsuka wa kimi ga narashiba no narashigao ni wa ori ni okosuru", with its charge of presumption.
This reply closes the sixty-eighth section. The prose passes no judgement; the section consists of the exchange alone. It too was included in the Gosen-shū.

The god who guards the leaves was believed to dwell in the kashiwa oak, and the poem starts from that belief.
The verb of dwelling is honorific, as befits a god, and the particle that follows is concessive: the god was there, and yet.
He admits he broke the branch without knowing, with an emphatic particle governing the verb.
The closing is a prohibition addressed to the god: let there be no curse. Toshiko, who reproached him, is cast as the god of the tree and duly propitiated. He concedes the fault and defuses it by elevating her, and never answers the reproach head on.
Source
Yamato Monogatari
Other