It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: Allah Almighty has said, "Whatever I have not decreed, the vow of the son of Adam cannot bring it to him. However, through this vow, I extract wealth from a miserly person; he gives Me that which, in his state of miserliness, he would never have given."
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 7297