Commentary for Numbers 10:5

ותקעתם תרועה WHEN YE BLOW AN ALARM — The signal for the camps to set out on the journey was a Tekiah, a Teruah (a tremulous sound) and again a Tekiah. Thus is it derived in the Siphre from the apparently redundant verses (Sifrei Bamidbar 73:2; cf. Rosh Hashanah 34a).

ותקעתם תרועה ונסעו המחנות החונים קדמה, seeing that this flag also had the carriers of the Tabernacle in its wake.

Tekiah, teruah, tekiah — this is how it is extrapolated by Sifri. For it is written “if you blow (תקעתם — from the same derivation as the word “tekiah”) a teruah” (v. 6) implying a tekiah followed by a teruah. It then written “a teruah they shall blow (יתקעו)” implying a teruah followed by a tekiah. How is this understood — as a tekiah, teruah, tekiah. We need not ask: Why then do we not have two teruos in the middle? Because we never find two teruahs one after the other. The reason for having written “teruah” twice is that one is needed for a gezeirah shavah (Scriptural comparison) to Yom Kippur, and any gezeirah shavah is based upon superfluous wording.

החונים קדמה, “who were encamped on the eastern side;” the flag of the army group headed by Yehudah.