Section 13. Whoever wilfully deprives an officer or enlisted person of his employment, or denies him employment, or prevents his being employed by another, or obstructs or annoys him or his employer in respect of his trade, business or employment, because of his connection with the armed forces of the commonwealth, or because of his necessary absence from business in performance of his duty as such, and whoever dissuades any person from enlisting in the said armed forces of the commonwealth by threat of injury to him in respect of his employment, trade or business, or of other injury, if he shall so enlist, shall be punished by a fine of not more than five hundred dollars, or by imprisonment for not more than six months, or both.