A mortgage payment, which is made up of principle and interest costs, is paid in arrears (what is owed from before). This can be very helpful to know if you're trying to plan a move around your lease terms.
Example: Let’s say your closing date is March 15. You will be charged prorated daily interest from March 15 through March 31 on your closing statement. The interest collected at closing will cover the interest due on your mortgage for those last 16 days in March. Then, your first mortgage payment will be due May 1, and that payment will include the interest due for April. This information can help with timing your move if you are tied to your current lease.