Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: The Prophet (peace and blessings be upon him) forbade showing humility (out of flattery) towards the well-off.
Imam al-Tabarani recorded it; its chain contains a narrator, Dawud bin al-Zibriqan, and he is matruk (abandoned).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الزهد / 17938