I am writing to provide an explanation for the gap in my employment history as indicated in my mortgage application. It's best to keep your letter of explanation short and sweet.Include as much detail as needed, but address only the specific information the lender requested. Mortgage lenders might request a letter of explanation for various red flags that come up in underwriting. Learn how to write one, and download a template. Explain what caused the employment gap, and be honest about it. There are lots of reasons why people aren't employed. If you want to write a letter of explanation for a mortgage lender, you'll need to provide clarifying information about your finances. A letter of explanation consists of short descriptions you can use to fill in the gaps in your paperwork for your underwriter. A letter of explanation can clarify your financial situation and get you one step closer to qualifying for a mortgage.