وَصَبِيتٍ مِنَ الْعَوَاتِكِ لَا تَنْسَاهُ إِلَّا مُبَيِّضَةٌ رَعْلَاءُ
Meaning: And there was a company of noble people whose presence, the poet implies, could be matched only by a great white-clad force.
Ṣabīt denotes a group. The commentary explains al-ʿawātik as noble young women. Mubayyaḍah raʿlāʾ can evoke an extensive white-armoured formation; the commentary also records the image of long pale swords.
The archaic terms admit interpretive variation. Rather than forcing one rigid pictorial detail, the central contrast is between a respected group and the conspicuous, formidable military force associated with it.