מַה־נָּאו֨וּ עַל־הֶהָרִ֜ים רַגְלֵ֣י מְבַשֵּׂ֗ר מַשְׁמִ֧יעַ שָׁל֛וֹם מְבַשֵּׂ֥ר ט֖וֹב מַשְׁמִ֣יעַ יְשׁוּעָ֑ה אֹמֵ֥ר לְצִיּ֖וֹן מָלַ֥ךְ אֱלֹהָֽיִךְ׃
װי שײן זײַנען אױף די בערגדי פֿיס פֿון דעם אָנזאָגערװאָס לאָזט הערן שלום, װאָס זאָגט גוטס, װאָס לאָזט הערן הילף: װאָס זאָגט צו צִיון: דײַן גאָט טוט קיניגן.
Ramban
And G-d Whom alone I shall fear He shall save me from the day of wrath.20Zephaniah 1:15. He shall keep me from mistakes And from all sin and transgression, And He shall lead me in the straight way And open for us the gates of light, And He shall deem us worthy To see the day of tidings,21“The day of tidings” was to Ramban a reality which was to transpire in the very near future. See his commentary further, 2:3, towards the end of the verse. As it is written: How beautiful upon the mountains Are the feet of the messenger of good tidings That announceth peace, The harbinger of good tidings That announceth salvation, That saith to Zion: ‘Thy G-d reigneth.’22Isaiah 52:7.
Rashi
O herald of Zion Heb. מְבַשֶּׂרֶת. The prophets who herald Zion. [This is the feminine form.] Elsewhere (infra 52:7), he says, “the feet of the herald (מְבַשֵּׂר).” [This is the masculine form.] This denotes that if they are worthy, he will be as swift as a male. If they are not worthy, he will be as weak as a female and will delay his steps until the end.
Rabbeinu Bahya
ראשונה יסעו, “they are to be the first ones to journey.” Our sages in Tanchuma Bamidbar 14 mention that wherever you look throughout the Scriptures you will always find the tribe of Yehudah mentioned first, being in the forefront. This is true in connection with the journeys, the encampments, the offering of the inaugural sacrifices, the battles against the Canaanites remaining after Joshua’s death (Judges 1,1-2). The same will hold true in the future when the message of the impending redemption will arrive; Yehudah will be the first one to proclaim it as we know from Isaiah 52,7: ”how welcome on the mountain are the footsteps of the herald announcing happiness, heralding good fortune; announcing victory, telling Zion, “Your G’d is King!” Similarly, in Nachum 2,1: “Behold on the hills the footsteps of a herald announcing good fortune! Celebrate your festivals O Yehudah.” [In both verses quoted it is Yehudah who is addressed. Ed.]