An anecdote about Rabbi Avraham of Chekhanov

(from Siach Sarfei Kodesh, 1989 ed. pt.iv, p.5, #3; my translation)

I heard from an old hasid that every time that the holy Rabbi Wolf of Strikov¹ came to the holy Rabbi from Kotzk², he had to tell him something about his holy father Rabbi Avraham of Chekhanov³. Once, he came to Kotzk and the Kotzker Rebbe asked him to tell him something about his holy father. Rabby Wolf replied that he didn't have anything to say. The Kotzker Rabbi was surprised and asked him "Do you really have nothing to say?"
At this point Rabbi Wolf recalled that when he was taking leave of his holy father before traveling to Kotzk and was in a big hurry, his father asked his mother to give him a saucer of tea to drink before his trip. His mother gave him the tea, but he didn't drink it and it just sat there . His father asked him why he wasn't drinking, and he answered that "it's overcooked (ie boiling hot)" (Yiddish: "s'ist kachidig"). Hearing this, his father shouted at him: "Didn't our Sages say (Shabbat 40): 'A secondary vessel does not cook'"?⁴ To this the holy Rabbi of Kotzk replied: "This is what I wanted to hear."

From this we can understand their greatness, that the holy Gaon of Chekhanov could not bear to hear language containing even a hint that went against the words of our Sages⁵.

¹Rabbi Ze'ev Wolf of Strikov (1807–1891)

²Rabbi Menaḥem Mendel of Kotsk (1787–1859)

³Rabbi Avraham Landau of Chekhanov (1784–1875)

⁴"R. Isaac b. Abdimi said: I once followed Rabbi into the baths, and wished to place a cruse of oil for him in the bath. Whereupon be said to me, Take [some water] in a second vessel  and put [the cruse of oil in it]. Three things are inferred from this: 1. Oil is subject to [the prohibition of] boiling; 2. a second vessel cannot boil; 3. making it lukewarm is boiling it". (BT, Shabbat 40a)

⁵In Yiddish the word for "boiling hot" (kachidig) comes from the word "to cook" (kochen).