This statement you make sounds like you may have some doubt about being able to pay your mortgage. That is not faith. Romans 4:17 says that faith is calling those things that be not as though they were. So, what should you be saying that is of faith? The mortgage is not paid at this time, but you hope it will be paid by a certain date. Faith says, it shall be paid by a certain date. That is speaking the way God speaks. God said in the beginning, "let there be light" before there was any light, and there was light. You should be saying, "I declare this mortgage paid on (date)." or, "This mortgage is paid on time and in full."
In the name of Jesus, be blessed, you are a blessing.