It was narrated that:
Thawban said: "When the Verse concerning silver and gold was revealed, they said: 'What kind of wealth should we acquire?' Umar said: 'I will tell you about that.' So he rode on his camel and caught up with the Prophet, and I followed him. He said: 'O Messenger of Allah what kind of wealth should we acquire?' He said: 'Let one of you acquire a thankful heart, a tongue that remembers Allah and a believing wife who will help him with regard to the Hereafter.' "
English reference: Vol. 3, Book 9, Hadith 1856
Arabic reference: Book 9, Hadith 1929