Lift up your eyes round about, and behold: all these gather themselves together, and come to you. As I live,
says the LORD,
you shall surely clothe yourself with them all, as with an ornament, and bind them on you, as a bride does.
Read Chapter 49
Ambrose of Milan
AD 397
In the passion of his body [Christ] washed the nations with his blood. Truly the mantle represents the nations, as it is written, “As I live, says the Lord, unless I shall clothe myself with them all, as with a garment,” and in another passage, “Like clothing you will change them, and they will be changed.” And so with his own blood he cleansed not his own sins, for there were none, but the offenses that we committed. - "On the Patriarchs 4.24"
Spiritual preparation produces faith in the one Lord, and this faith is the opportunity for salvation, through which there is a coming to the knowledge of God through baptism and the doing of various noble works for the hope of eternal life. Their souls are compared with various choice gems, and the church is shown to be fashioned with a crown. - "Exposition of Song of Songs 7.13"
If anyone asks what the Lord’s garments, which became white as snow, represent typologically, we can properly understand them as pointing to the church of his saints. Of them Isaiah said, “You will be clothed with all of these as though with an ornament.” - "Homilies on the Gospels 1.24"
What, then, is the message promised by the divine words? Namely, the calling and assembling of those who were scattered and a return in the spirit for those who were lost and a way back for those who fled, and a return and a reawakening as well as the reward of love for Christ.… “And I have put them on” says the Lord, “to be the ornament of a bride.” Such is the beautiful order of the churches. For it is customary in the divinely breathed Scriptures to decorate the church with gold and colors. - "Commentary on Isaiah 4.4.49.18"
Happy are those ones of so great merit and so great virtue that they can be called the ornament of the church! I think that different spiritual graces are meant here, through which the display of the bride is decorated, of whom it speaks in Psalm 44. - "Commentary on Isaiah 13.23"