The exchange rate
Stated once, plainly, and it is not symmetrical.
مَن جَآءَ بِٱلْحَسَنَةِ فَلَهُۥ عَشْرُ أَمْثَالِهَا ۖ وَمَن جَآءَ بِٱلسَّيِّئَةِ فَلَا يُجْزَىٰٓ إِلَّا مِثْلَهَا وَهُمْ لَا يُظْلَمُونَ
Man jā'a bi-l-ḥasanati fa-lahu ʿashru amthālihā, wa man jā'a bi-s-sayyi'ati fa-lā yujzā illā mithlahā…
“Whoever comes [on the Day of Judgement] with a good deed will have ten times the like thereof [to his credit], and whoever comes with an evil deed will not be recompensed except the like thereof; and they will not be wronged.1”
Source
The Qur'an · 6:160
Qur'an
- Qur'anic text in the Uthmani script via Quran.com; translation: Saheeh International