文帝之後六年，匈奴大入邊。乃以宗正劉禮為將軍，軍霸上；祝茲侯徐厲為將軍，軍棘門；以河內守亞夫為將軍，軍細柳，以備胡。

In the sixth year of the Later Era under Emperor Wen, the Xiongnu invaded the border on a large scale. The emperor thus appointed three commanders for defense: Liu Li, the Minister of the Imperial Clan, stationed at Bashang; Xu Li, the Marquis of Zhuzi, at Jimen; and Zhou Yafu, the Governor of Henei, at Xiliu, to guard against the invaders.

上自勞軍。至霸上及棘門軍，直馳入，將以下騎送迎。已而之細柳軍，軍士吏被甲，銳兵刃，彀弓弩，持滿。天子先驅至，不得入。先驅曰：“天子且至！”軍門都尉曰：“將軍令曰：‘軍中聞將軍令，不聞天子之詔。’”居無何，上至，又不得入。於是上乃使使持節詔將軍：“吾欲入勞軍。”亞夫乃傳言開壁門。壁門士吏謂從屬車騎曰：“將軍約，軍中不得驅馳。”於是天子乃按轡徐行。至營，將軍亞夫持兵揖曰：“介冑之士不拜，請以軍禮見。”天子為動，改容式車，使人稱謝：“皇帝敬勞將軍。”成禮而去。

Emperor Wen personally toured the garrisons to boost the troops morale. At Bashang and Jimen, the imperial procession galloped straight into the camps, where the commanding officers, followed by their cavalry, rode out to welcome and escort him. Subsequently, he arrived at the Xiliu garrison. There, every officer and soldier was clad in armor, their weapons sharpened, bows drawn to the full, and crossbows ready. The imperial vanguard reached the gate but was barred from entry. "The Son of Heaven is approaching!" declared the vanguard. The captain at the gate responded, "The general has ordered: In the army, we heed only the generals commands, not the emperors edict." Shortly after, the emperor himself arrived, yet was still denied entry. Thereupon, the emperor dispatched a messenger with his ceremonial tally to inform the general: "I wish to enter to encourage the troops." Only then did Zhou Yafu give the order to open the gate. The guard at the gate instructed the emperors accompanying riders, "The general has stipulated: no galloping is permitted within the camp." The Son of Heaven therefore reined in his carriage and proceeded at a slow pace. Upon reaching the headquarters, General Zhou Yafu, clasping his hands while holding a weapon, said, "A man in armor does not perform the full kneeling ceremony. I beg to salute you with military rites." The emperor, deeply impressed, altered his expression and leaned forward on the carriage crossbar in response. He sent someone to convey his respects: "The emperor respectfully encourages the general." The ceremony was thus completed, and the emperor departed.

既出軍門，群臣皆驚。文帝曰：“嗟呼，此真將軍矣！曩者霸上、棘門軍，若兒戲耳，其將固可襲而虜也。至於亞夫，可得而犯邪？”稱善者久之。

Once outside the camp gate, all the ministers were astounded. Emperor Wen exclaimed, "Alas, this is a true general! The garrisons at Bashang and Jimen were merely childs play. Their commanders could easily be captured by a surprise attack. But as for Zhou Yafu, how could the enemy dare to violate him?" He praised Zhou Yafu for a long time.