But if he thrust him suddenly... — See Deuteronomy 19:4-5, where the meaning of the law is illustrated.
Related Commentaries of Numbers 35:22
Numbers 35:22-23
22 But if he thrust him suddenly without enmity, or have cast upon him any thing without laying of wait,
23 Or with any stone, wherewith a man may die, seeing him not, and cast it upon him, that he die, and was not his enemy, neither sought his harm: