Is a purchaser required to indemnify the vendor against the mortgagee following the assumption of a mortgage?

Although the question involved the obligation of a purchaser to indemnify the vendor against the mortgagee following the assumption of a mortgage, the distinction between a sale of land and a sale of an equity of redemption was discussed in Williston v. Lawson (1891), 1891 CanLII 75 (SCC), 19 S.C.R. 673. Strong J. said at pp. 677-78: “It is important to distinguish between a sale of the land itself, though in fact subject to encumbrances, and a sale of the equity of redemption the purchaser assuming the encumbrances, inasmuch as the rights of the parties in carrying out the sale are not the same. “If the land itself was sold then, a good title having been shown, or the purchaser having accepted the title, the vendor is bound to procure the concurrence of the mortgagee in the conveyance, he being paid off in the first instance by the vendor or by an appropriation of a sufficient part of the purchase money. The encumbrance in such a case does not constitute an objection to the title but is said to be a matter of conveyancing, that is to say, a matter respecting the completion of the sale by a conveyance ... “In the case of a sale of an equity of redemption, in other words a sale of land in mortgage upon the terms that the purchaser is to take a conveyance of the mere equity of redemption paying the vendor the specified price for that, a court of equity assumes (unless there is some agreement to the contrary) that the purchaser is to indemnify the vendor against the mortgage if there is any personal liability on his part in respect of it.”