Nedarim 40b — the Talmud in English

For Shmuel said: Water does not purify when flowing,

because we are concerned that the collected waters have become more abundant than the flowing waters —

but

in the Euphrates River

only on the days of Tishrei,

since then it is neither the season of rainfall nor the time of the melting of snow, and at that time we are not concerned about an abundance of collected waters .

Shmuel’s father made ritual baths for his daughters on the days of Nisan,

since he was then concerned about the melting of snow, and therefore he did not allow them to immerse in flowing water in the month of Nisan.

And mats

there were mats beneath their feet in the river, so that the mud at the bottom of the river would not interpose between their feet and the water

on the days of Tishrei,

when he allowed them to immerse in the river, since there was no concern for collected waters [and during the other days of autumn and winter they immersed in the ritual baths in the houses because of the cold].

Rav Ami said in the name of Rav: What is [the meaning of] that which is written

which the Holy One, blessed be He, said to Ezekiel:

“And you, son of man, make for yourself implements of exile”?

What are those implements specifically associated with exile?