I will dwell in the midst of thee, saith the Lord - This must chiefly refer to the Christian church, in which God ever dwells by the power of his Spirit, as he had done by the symbol of his presence in the first Jewish temple.
Sing and rejoice, O daughter of Zion - It is a great jubilee of joy, to which Zion is invited. Thrice beside is she invited with this same word, and all for the restored or renewed Presence of God. “Cry aloud for joy, thou barren which bare not” Isaiah 54:1, as here, on the coming in of the Gentiles, “Cry aloud for joy, O daughter of Zion; jubilate, O Israel; rejoice and exult with all the heart, O daughter of Jerusalem; the Lord, the King of Israel, is in the midst of thee” Zephaniah 3:14-15. “Shout and cry aloud for joy, O inhabitant of Zion; for great in the midst of thee is the Holy One of Israel” Isaiah 12:6. The source of joy is a fresh coming of God, a coming, whereby He should dwell abidingly among them: truly what is this, but the Incarnation? As John saith, “The Word was made Flesh and dwelt among us” John 1:14; and, “Behold the tabernacle of God is with men, and He will dwell with them, and they shall be His people, and God Himself shall be with them and shall be their God” Revelation 21:3.
Cyril: “Hence too you may learn how great a subject of contentment above is the Presence of the Saviour upon earth. He could not then but bid the spiritual Zion, “which is the Church of the Living God” 1 Timothy 3:15, the most sacred multitude of those saved by faith, to cry aloud for joy and rejoice. But it was announced that He should come and be in the midst of her. For John saith to us, The Word “was in the world” John 1:10, and, being God, was not severed from His creatures, but He was Himself the Source of life to all living, and holding all things together to well-being and life; but “the world knew Him not” John 1:10: for it worshiped the creature. But He came among us, when, taking our likeness, He was conceived by the holy Virgin, and “was seen upon earth and conversed with men”, and the divine David witnesseth saying, “Our God shall come manifestly, and shall not keep silence” Psalm 50:3. Then also was there a haven for the Gentiles. For now no longer was the race of Israel alone taught, but the whole earth was engoldened with the evangelical preachings, and in every nation and country “great is His Name.”
Jerome: “This too is to be understood of the Person of the Lord, that He exhorts His people, being restored from the captivity to their former abode, to be glad and rejoice, because the Lord Himself cometh and dwelleth in the midst of her, and many nations shall believe in Him, of whom it is said, “Ask of Me and I will give Thee nations for Thine inheritance, and the ends of the earth for Thy possession” Psalm 2:8, and He shall dwell in the midst of them, as He saith to His disciples, “Lo, I am with you always, even unto the end of the world” Matthew 28:20.