Top secret
PersonalCopy to Comrades Kamenev and Zinoviev
Dear Comrade Stalin:
You have been so rude as to summon my wife to the telephone and use bad language. Although she had told you that she was prepared to forget this, the fact nevertheless became known through her to Zinoviev and Kamenev. I have no intention of forgetting so easily what has been done against me, and it goes without saying that what has been done against my wife I consider having been done against me as well. I ask you, therefore, to think it over whether you are prepared to withdraw what you have said and to make your apologies, or whether you prefer that relations between us should be broken off.[1]
Respectfully yours,
LeninMarch 5, 1923
https://www.marxists.org/archive/lenin/works/1923/mar/05.htm
The footnote there appears to confirm that he did indeed apologize.
Also, we don’t know exactly what it means that “he was rude”. How rude exactly? What kind of “bad language”? In what context? I can imagine how, if he was worried about Lenin’s health and annoyed at the fact that Lenin was not being sufficiently allowed to rest, he would lose his calm and use some expletives. We can’t forget that historical figures were just human too.