Strive not with a man without cause, if he have done thee no harm.
– Proverbs 3:30
Strive and cause can have legal connotations, i.e. suing in court. It need not go that far. It can also refer to any contention or strife. Wisdom teaches not to enter into contention or strife without good reason. We are to avoid it and live peaceably with all as much as is possible (Romans 12:18-21).