At the time of the establishment of the Western Zhou Dynasty, there were about eight hundred princely states on the land of China, with the passage of time, reaching the Spring and Autumn Warring States period, the princely states were only a little more than a hundred, before the Spring and Autumn Warring States, the world was the world of Zhou Tianzi, during the Spring and Autumn Period, the princely states gradually no longer obeyed the orders of the Zhou royal family, and began to gradually annex weak and small countries, but in the Qin Mugong period, there was a three-peace Jin rebellion, why not take the opportunity to annex the Jin state, so that there would be no later Han Zhao Wei three families divided into Jin, the date of the unification of the world will not be postponed for hundreds of years.

During the reign of Duke Mu of Qin, he exerted great efforts to govern, appointed Baili Xi and Uncle Jian as ministers, vigorously reformed the country, so that the national strength of the Qin state gradually increased, during his reign, he successively destroyed the small states of Liang, Rui, and Shui, he added a thousand miles of territory for the Qin state, achieved a generation of hegemony, and his merit also lies in quelling the Jin rebellion three times and concluding the good of Qin and Jin.
When Duke Xian of Jin reigned, he made improper arrangements for his heir to the throne, resulting in his sons competing with each other for the throne after his death, after Xi Qi succeeded to the throne, he was killed by the chancellor Rick, and there was chaos within the Jin state, Qin Mugong in order to reflect his hegemonic status, led troops to escort the prince YiWu to inherit the throne, before sending troops, Yiwu promised to cede the eight cities of Hexi to the Qin state, first to thank the Qin duke for his friendship, and second, as a cost to the army, but after Yi Wu inherited the throne, he not only did not give thanks, but also sent troops to attack the Qin state.
In the face of natural disasters and man-made disasters, the State of Qin borrowed grain from the State of Jin, Yi Wu did not remember the grace of sending troops to support the establishment of the army and the grace of the State of Qin borrowing grain in the face of the disaster in the later Jin State, but instead sent troops to attack the State of Qin, the Qin army was on the battlefield, bravely killed the enemy, and as far as possible captured the Duke of Jin Hui, the monarch was captured, the State of Jin was in chaos, and finally Zhou Tianzi came forward to break the siege, Qin Mugong's wife was the sister of The Duke of Jin, and Mu Ji also interceded with Mu Gong, so in this case, Qin Mu Gong had to release Yi Wu and once again quell the turmoil in the Jin State.
Twenty-three years after the Duke of Qin Mugong, Duke Huai of Jin succeeded to the throne, loyal to the internal slaughter, externally in order to prevent The Heavy Ear from returning to the country and competing for the throne himself, sent people to assassinate the Heavy Ear, and the Heavy Ear returned to the Jin State to compete for the throne under the protection of The Duke of Qin Mu, and the soldiers and people of the State of Jin all knew the virtues of the Heavy Ear and came to surrender, but there were always people with bad intentions, in order to avenge the ancestors and create chaos, after the Heavy Ear knew the news, he secretly sneaked back to the Qin State, and with the help of the Qin State, he led the army back to the Jin State, and he worked hard to govern, so that the Jin State gradually stabilized.
Qin Mugong thus quelled the turmoil of the Jin state three times, and in the era when the various princely states were fighting each other, why did the Qin state not take the opportunity to destroy the Jin state, if it is benevolent, Qin Mugong destroyed more than twenty countries during his reign, so there is another reason for the Qin state not to destroy the Jin state.
During the reign of Qin Mugong, although the State of Qin destroyed many countries, but those were some small countries, the State of Jin was a large country at that time, the latter three families were divided into Jin to establish Han Zhao Wei, a country became three kingdoms, you can imagine how powerful the strength of the State of Jin is, so the State of Qin does not have the strength to destroy the State of Jin; the State of Qin and the State of Jin have a relationship of in-laws, their purpose is only to dominate, the existence of the State of Jin can be used as a kind of help for themselves, and at the same time, the State of Jin is in the east of the State of Qin, and can resist the attacks of other countries in the Central Plains There is also that although there were conquests between countries at that time, they were nominally constrained by Zhou Tianzi, and it was possible to encroach on the land of other countries, and generally did not let them extinct, and the monarch of the Jin state was a descendant of the Zhou royal family, so at that time the Qin state would not destroy the Jin state.
Qin Mugong Sanping Jin Chaos, nothing more than to get a certain amount of income, for his own hegemony, not really want to help the Jin State, he under the slogan of benevolence, on the surface is to defend the royal family, in fact, it is just a hypocrisy.