She shall be brought unto the King in raiment of needlework; i.e. in garments richly embroidered. Such were known to the Hebrews from the time of the Exodus (Exodus 28:4, Exodus 28:39), and were worn by princeases in David's day (2 Samuel 13:18).
Brides were commonly "led" into the presence of the bridegroom. The virgins her companions that follow her shall be brought unto thee (comp. Psalms 45:9). A virgin train follows the bride as she is led to the palace of the bridegroom, for a royal bride necessarily had her attendants.
These symbolize the Gentile converts that should attach themselves to the original Church, and follow that Church into Christ's presence.