The text is from Isaiah 40:9: "Get you up to a high mountain, O Zion, herald of good news; lift up your voice with strength, O Jerusalem, herald of good news; lift it up, fear not; say to the cities of Judah, 'Behold your God!'" and from Isaiah 60:1: "Arise, shine, for your light has come, and the glory of the LORD has risen upon you."
The "lift[ing] up" mentioned in this section is emphasized by a rising melody.
Similarly, the "arise"s have an upward trend.