No.  Only the profit (capital gain) is taxable, not the sale amount.  However, the sale must be reported on your tax return.

You may actually have a deductible capital loss, since it's unlikely that the cost basis (purchase price) and sale amount are exactly $70,000 considering the expenses of sale.

Don't forget there was probably expenses to purchase as well  .... purchase price + cost to purchase + cost to sell = basis in property.     Selling price - basis = gain/loss  which must be reported on the return either way.