Sentence:  Our people are daily gaining Health Spirits and Discipline &mdash; the spade & pick axe throw'd aside &mdash; for the British Rebels to take up &mdash; they notwithstanding affect to hold us cheap and threaten to <WSD>beat up</WSD> our Quarters — "if we don't" <WSD>beat up</WSD> theirs first which is in Contemplation, "this in time". 
Meaning of the word marked with <WSD> tags:  To attack suddenly; to alarm.