Also, there is a difference between a loan and a withdrawal. For a traditional IRA you can withdraw up to $10,000 for the purchase of your first home. You will still pay taxes on that $10K, but the 10% early withdrawal penalty will be forgiven. However, there is no such provision for a 403(b). If you withdraw from a 403(b) and are not of retirement age yet, you will pay taxes on that withdrawal, as well as the 10% early withdrawal fee.
If you take out a loan against your 403(b) you need to be aware of the $EXPENSIVE$ consequences of defaulting on the loan. So talk to your plan administrator about this to get the facts based on the rules that apply to your specific plan.
