《汉书·传·淮南衡山济北王传》
这时恰巧有人愿意从军的可到长安，雷被随即要求去击匈奴。
此时有欲从军者辄诣长安，被即愿奋击匈奴。
At this time, it happened that someone volunteered to join the army and could go to Chang'an. Lei Bei immediately asked to go and fight the Huns.