Getting behind on your mortgage is not the best thing to do for your credit score but getting behind on your mortgage payments by a few months is usually not gonna result in foreclosure as long as you get caught up with the payments.
Most banks will not start the foreclosure process until you're 3 or 4 months behind on your mortgage payments.
But some banks may try to foreclose after 2 months so check with your bank to be sure as it can vary from bank to bank.
When you stop making mortgage payments you're going against the terms and conditions in the agreement that you agreed to when you signed for the mortgage.
The bank wants there mortgage payments to pay back the loan they lent you for the home you're living in.
I have been behind a couple months on my mortgage when I lost a job but when I got my new job I also got a temporary loan from another bank and paid those mortgage payments in full and I also spoke with the bank to let them know what was going on.
They worked with me and I didn't get threatened with foreclosure and they didn't report it to my credit score so it didn't lower my credit score.