To al-Haarith al-Hamdani
Nahj al-Balāgha|Volume 1|Book 2|Chapter 69
وَاسْتَصْلِحْ كُلَّ نِعْمَةٍ أَنْعَمَهَا اللهُ عَلَيْكَ، وَلَا تُضَيِّعَنَّ نِعْمَةً مِنْ نِعَمِ اللهِ عِنْدَكَ، وَلْيُرَ عَلَيْكَ أَثَرُ مَا أَنْعَمَ اللهُ بِهِ عَلَيْكَ.
Seek good out of every favour that Allāh has bestowed on you, and do not waste any favour of Allāh over you. The effect of Allāh’s favours over you should be visible on you.