וּתְקַעְתֶּ֖ם תְּרוּעָ֑ה וְנָֽסְעוּ֙ הַֽמַּחֲנ֔וֹת הַחֹנִ֖ים קֵֽדְמָה׃
און אַז איר װעט בלאָזן אַ שאַלרוף, זאָלן ציִען די לאַגערן װאָס לאַגערן צו מזרח.
Rashi
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).
Sforno
ותקעתם תרועה ונסעו המחנות החונים קדמה, seeing that this flag also had the carriers of the Tabernacle in its wake.
Chizkuni
החונים קדמה, “who were encamped on the eastern side;” the flag of the army group headed by Yehudah.