In that day - This verse commences a new subject, and affirms that while the kingdom of Israel should be destroyed, the kingdom of Judah would be preserved, and restored (compare Isa. 7–9)
Be for a crown of glory - He shall reign there as its king, and he shall guard and defend the remnant of his people there. This reign of Yahweh shall be to them better than palaces, towers, walls, and fruitful fields, and shall be a more glorious ornament than the proud city of Samaria was to the kingdom of Israel.
And for a diadem of beauty - A beautiful garland. The phrase stands opposed to the wreath of flowers or the diadem which was represented Isaiah 28:1, Isaiah 28:3 as adorning the kingdom and capital of Israel. Yahweh and his government would be to them their chief glory and ornament.
Unto the residue of his people - To the kingdom of Judah, comprising the two tribes of Judah and Benjamin. This doubtless refers to the comparatively prosperous and happy times of the reign of Hezekiah.