The conditional judgment shall be that if the mortgagor, his heirs, executor or administrator pays the sum that the court adjudges to be due and payable, with interest, within 2 months from the time of judgment, and pays such other sums as the court adjudges to be thereafter payable, within 2 months from the time that they fall due, no writ of possession shall issue and the mortgage shall be void. Otherwise it shall issue in due form of law, upon the first failure to pay according to said judgment. If, after 3 years from the rendition of the judgment, the writ of possession has not been served or the judgment wholly satisfied, another conditional judgment may, on motion filed in the name of the mortgagee or assignee, be rendered, and a writ of possession issued as before provided. When the condition is for doing some other act than the payment of money, the court may vary the conditional judgment as the circumstances require. The writ of possession shall issue if the terms of the conditional judgment are not complied with within the 2 months.