Ibn Abi Najih narrates from Mujahid and Tawus (may Allah have mercy on them both) concerning the saying of Allah Almighty "if you know any good in them" [Surah al-Nur: 33]: khayr (good) here means "wealth and trustworthiness."
(b) Yunus narrates from al-Hasan (may Allah have mercy on him) that it means truthfulness, fulfilling (obligations) completely, and trustworthiness.
(c) Mughirah narrates from Ibrahim (may Allah have mercy on him) that it means truthfulness and fulfilment.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المكاتب / 21609