Why is studying Hadith important?

Al Khateeb Al Baghdaadi said in Sharaf Ashaab al Hadeeth p.7-9:

If the person of blameworthy opinion busied himself with the beneficial knowledge and sought the Sunnah of the Messenger of the Lord of the worlds and followed the footsteps of the jurists and hadith scholars, he would find therein sufficiency from anything else. He would be content with the narrations over his own opinion, because hadith encompasses the knowledge of the fundamentals of Tawheed (monotheism), the explanation of the aspects of promise and warning, the attributes of the Lord of the worlds, exalted above the statements of the heretics, information about the qualities of Paradise and Hell and what Allah has prepared therein for the pious and the wicked, what Allah created in the earths and heavens of various wonders and great signs, the mention of the angels drawn near (to Allah), and the description of those who stand in rows and glorify (Allah).

In hadith, there are stories of the prophets, tales of the ascetics and saints, exhortations of the eloquent, sayings of the jurists, biographies of the kings of Arabs and non-Arabs, stories of the previous nations, explanation of the battles and expeditions of the Messenger ﷺ, the summary of his rulings and judgments, his sermons and admonitions, his signs and miracles, the number of his wives, children, in-laws, and companions, and the mention of their virtues and merits, the explanation of their stories and biographies, their lifespans, and the clarification of their lineages. Therein is the interpretation of the Magnificent Qur’an and the news and wise reminder it contains.

The statements of the Companions regarding the rulings preserved from them and mentioning those who held the view of each of them from the Imams who came after them and the mujtahid scholars. Allah has made its people the pillars of the Shari’ah and through them He demolished every abominable innovation. They are the trustees of Allah among His creation, the intermediaries between the Prophet ﷺ and his nation, and the ones who strive in preserving his religion. Their lights shine bright and their virtues are widespread. Their signs are dazzling, their ways are manifest, and their proofs are overwhelming. Every group aligns with a desire to which it returns or approves of an opinion it devotes itself to, except the people of hadith, for the Book is their provision, the Sunnah is their proof, and the Messenger is their group and to him is their affiliation. They do not turn to desires nor pay attention to opinions.

What they narrate from the Messenger is accepted from them, and they are the ones entrusted with it and just. They are the preservers and treasurers of religion, the vessels and bearers of knowledge. When there is a disagreement regarding a hadith, the reference is to them, and whatever they rule by is accepted and heard.

Among them are learned jurists, lofty and noble leaders, ascetics in every tribe, those distinguished with virtues, proficient reciters, and excellent orators. They are the great majority and their way is the straight path. Every innovator outwardly conforms with their beliefs and does not dare to openly express other than their views.

Whoever plots against them, Allah will crush him, and whoever opposes them, Allah will forsake him. Those who forsake them cannot harm them, and those who shun them will never succeed. The one who is cautious in his religion is in need of their guidance, and the one who looks at them with an evil eye will be left helpless. Indeed, Allah is capable of supporting them.”

And Allah knows best!