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Is it more important to say Vehu Rachum or to say Tachanun?
What happens if there is insufficient time to recite both Vehu Rachum
and the rest of the Tachanun together with the tzibur?
It seems that one should recite Tachanun with the tzibur and “Vehu
Rachum” after davening.
It should be noted that the commentaries dispute what is included in
the takanah of reciting Vehu Rachum. Some contend that the takanah is
to say Vehu Rachum, and to say it while standing (Shulchan Aruch,
Orach Chayim 134:1), whereas others explain that the takanah included
only reciting Vehu Rachum, but did not require one to stand (Levush).
(They all agree, however, that one should recite Vehu Rachum while
Vehu Rachum should be treated with the kedusha of the Shemoneh Esrei
(Magen Avraham). Therefore, there are those who contend that it should
be said quietly (Rama 134:1). However, the Beis Yosef rules that one
may say Vehu Rachum aloud, as is the custom of many people.