This letter was appended to the kuntres sent out for Yud-Beis Tammuz, 5710.1

At this opportunity, I would like to clarify our custom in response to questions asked by many: [When] Rosh Chodesh Menachem Av falls on Shabbos, do we read the passage beginning HaShamayim Kisii2 or the passage beginning Shimu Dvar A‑donai as the Haftorah?3

[In resolution,] I would like to cite a portion of my notes from my records of the year 5690 when Rosh Chodesh Menachem Av fell on Shabbos:

Motza’ei Shabbos, the eve of the Ninth of Menachem Av, 5690 (May this date be transformed into a day of rejoicing!), Berlin:4

I called on my revered father-in-law, the Rebbe, Shlita, who was resting on the sofa. He spoke about the custom concerning the Haftorah to be read on the Shabbos of Rosh Chodesh Menachem Av, saying: “My father [the Rebbe Rashab] once read HaShamayim Kisii. Several years later, when Rosh Chodesh Menachem Av again fell on Shabbos, he read Shimu Dvar A‑donai. At that time my father commented that he regretted having done otherwise on the previous occasion. ”

With regard to the debate between the various opinions see Shulchan Aruch, Orach Chayim, sec. 425 and its commentaries; Shaarei Ephraim, Shaar 9, sec. 22.