Surah Al-Muddaththir 74:6

وَلَا تَمْنُن تَسْتَكْثِرُ

And do not confer favor to acquire more.

Translation: Saheeh International

Tafsir

And do not grant a favour seeking greater gain read tastakthiru as a circumstantial qualifier in other words do not give something in order to demand more in return this stipulation is specific to the Prophet s since he is enjoined to adopt the fairest traits and the noblest of manners;

Excerpt from Tafsir al-Jalalayn, commentary on 74:6, via Quran.com. The reader has the full commentary and 9 more tafsirs.