In the case of a sale as provided for in the preceding rule, the purchaser of the property shall execute his bond, with two or more good and sufficient sureties, to be approved by the officer making the sale, and payable to such officer, in a sum not less than double the amount of the purchase money, conditioned that such purchaser shall pay such purchase money at the expiration of the time given.
Tex. R. Civ. P. 714