Massachusetts General Laws Part III. Courts, Judicial Officers and Proceedings in Civil Cases (Ch. 211-262) Ch. 246, § 63

The preceding sections shall not prevent the trustee from selling the property in his hands for payment of the claim for which it is mortgaged, pledged or otherwise liable at any time before the amount due him is paid or tendered as provided in section sixty or sixty-one, if such sale would be valid as between him and the defendant.