Massachusetts Constitution Pt. 2, Ch. I, § 2, Art. 5

ART. V. Provided nevertheless, that no person shall be capable of being elected as a senator, [who is not seised in his own right of a freehold within this commonwealth, of the value of three hundred pounds at least, or possessed of personal estate to the value of six hundred pounds at least, or of both to the amount of the same sum, and] who has not been an inhabitant of this commonwealth for the space of five years immediately preceding his election, and at the time of his election, he shall be an inhabitant in the district for which he shall be chosen.