Ata bin Abi Rabah says that what is meant by it is wealth. Then he recited this verse: "It is prescribed for you, when death approaches one of you, if he leaves behind good (wealth), that he make a bequest" [Surah al-Baqarah: 180]. Ata says that here khayr (good) means wealth. Ibn Abbas (may Allah be pleased with them both) says about "if you know any good in them" [Surah al-Nur: 33] and "And indeed he is intense in his love of good (wealth)" [Surah al-Adiyat: 8] that what is meant is wealth; and in "if he leaves behind good" [Surah al-Baqarah: 180], good means wealth. [Da'if]
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المكاتب / 21607