Is being repeatedly exposed to theft, despite striving for lawful earnings, a punishment or a test, and what is the way to safeguard one's wealth?

The prescribed approach for a Muslim when afflicted by calamities such as theft is to know that Allah expiates sins thereby and raises one's ranks. Thus, one should be patient and content, and it is not befitting to be preoccupied with whether it is a punishment or a test. There is no specific supplication for protecting money from theft, but there are general morning and evening remembrances and supplications that protect a Muslim from evil.