Bede

Now therefore take the spear that is at his head, etc. The spear either insinuates the power of the kingdom itself or the arms of spiritual virtues, by which the kingdom could be helped. However, it can be taken regarding the earthly kingdom they had and the heavenly kingdom they hoped for, which anyone among them knew to hope for. It is indeed established that both were rightfully taken away from the faithless. …

Commentary on Samuel ↗