Paying Down Mortgage Questions

[Jeff Cox]

I have tried searching because this question has probably been answered but lets say i don't need the money at the end of the year and i have NOI of like 12k. IF i were to just pay 12k on my principle would i still pay taxes on the 12k of profit since it now has gone back to mortgage payment? I understand using the money to buy more property etc etc but in this scenario lets just say im still working a good paying job and i dont need the money and im at the point where i am no longer going to be buying any more property. Will i pay taxes on the profit if im paying down the principle with all the money left over?