«فَمَالَتْ إِلَى اسْتِخْلَاصِ الْبَدْرِ التَّمِّ»
She inclined to secure the full moon.
Badr tamm literally means the full moon, but here refers to the shining silver coin. The metaphor presents a small payment as visually splendid. The wording does not say the dirham is *like* a moon; it directly calls the coin a moon.