See Full Constitution
Part Second

Article 93. Governor and Judges Prohibited From Holding Other Offices

No governor, or judge of the supreme judicial court, shall hold any office or place under the authority of this state, except such as by this constitution they are admitted to hold, saving that the judges of the said court may hold the offices of justice of the peace throughout the state; nor shall they hold any place or office, or receive any pension or salary, from any other state, government, or power, whatever.