Mortgage applications: Is there a legal requiremen to disclose all sources of income?

[Sam Young]

When applying for a mortgage is there a LEGAL obligation to disclose all income or can you disclose the income sources that will qualify you for the loan? For example, can I just disclose my employment income and not investment income? Same for savings and assets, do you have to disclose everything?  The property being financed is the collateral, so why would you need to disclose income and asset that are not needed to qualify? Note: I understand that all debts have to be disclosed.