In the name of Allah, Most Gracious, Most Merciful.
Umar ibn-Khattab (may Allah be pleased with him) narrates that the Messenger of Allah (May Allah exalt his mention and protect him from imperfection) said: Indeed, if you put your faith completedly in Allah, as it ought to be, then surely you will be provided sustenance as birds are provided for. They leave in the morning with their stomachs empty and return in the evening duly filled. (Tirmidhi)
Audio lecture on the meaning of this hadith can be found here.
Compiled by Muhammad Yousuf Kandhlavi
Chapter 1, Page 16, Number 31