Paying off a property in 3 years?

[Isaiah Cuellar]

Good morning everyone, I was wondering, if I want a property paid off in three years, and I put 20% down, should I put as much as I can monthly (I can add an extra $4,000 per month) or, should I put the $4,000 each month into a 5.8% interest rate CD, and wait until I have enough to pay off the principal cash? Common sense tells me put the money in CD’s to build more and let the tenant pay off the mortgage until I can pay it cash, but a lender told me the best way would be to put the $4,000 per month straight into the principal… was that just him trying to make more off of interest from me?