Mass. Gen. Laws ch. 136 § 16
All stores and shops which sell goods at retail may be open at any time on Sundays and on Memorial Day, Juneteenth Independence Day, July Fourth and Labor Day, but no such stores and shops may be open on Christmas Day if Christmas occurs on a Sunday. The performance of labor, business and work directly connected to retail sales on these days shall also be allowed. Stores and shops allowed to open under this section may sell on these days all types of goods and foodstuffs which may lawfully be offered for sale in the commonwealth other than alcoholic beverages. To the extent that this section is inconsistent with section 6 or any other general or special law, this section shall control.
Any store or shop that qualifies for exemption under clause (25), (27) or (50) of section 6 and employs more than 7 persons, including the proprietor, shall not require any employee to perform such work, and an employee's refusal to work for any retail establishment on a holiday shall not be grounds for discrimination, dismissal, discharge, reduction in hours or any other penalty. The terms "Memorial Day," "Juneteenth Independence Day," "July Fourth" and "Labor Day" shall mean the legal holidays on which said days are celebrated in accordance with clause eighteen of section seven of chapter four of the General Laws.
Mass. Gen. Laws ch. 136, § 16