As-Salaam alaikum,
As we know, the Sunnah refers to the commands, prohibitions, sayings, actions and tacit approvals of the Prophet Muhammad, Sallallahu alaihi Wasallam. Allah Ta'ala says in the Holy Qur'an, in clarifying the nature of the Beloved Prophet's behaviour, Sallallahu alaihi Wasallam:--

"YOUR COMPANION DOES NOT ERR, NOR DOES HE GO ASTRAY,
NOR DOES HE SPEAK OUT OF DESIRE- IT IS NAUGHT BUT REVELATION
THAT IS REVEALED." (53:2-4)

"CERTAINLY YOU HAVE IN THE MESSENGER OF ALLAH AN EXCELLENT
EXAMPLE FOR THE ONE WHO HOPES IN ALLAH AND THE LAST DAY, AND
REMEMBERS ALLAH MUCH." (33:21)

Thus we, as Muslims, should model ourselves upon this perfect examplar, imitating the Messenger of Allah, alaihi salaat was-salaam, as mush as we can, both in his character and his mode of action. And since the Prophet is "CLOSER TO THE BELIEVERS THAN THEIR [own] SELVES" (33:6), it can be said that he is indeed the believer's alter ego.

Sayyadi Abu Hamid al-Ghazzali (d. 1111), may Allah be Merciful to him, wrote of the true Muslim as one who 'imitates the Messenger of Allah in his goings out and his comings in, his movements and his times of rest, the manner of his eating, his deportment, his sleep and his speech. So a man should sit while putting on his trousers and stand while putting on his turban, start with the right foot when putting on his shoes and, when cutting his nails, begin with the forefinger of the right hand...' in every facet of life, there is an example set by the Noble Prophet, Sallallahu alaihi Wasallam.

Indeed, the Sunnah of the Prophet, alaihi salaat was-salaam, provides not only a framework but also, as it were, a network of channels into which the believer's will enters and through which it flows smoothly.. both guided and guarded. The Sunnah is the application of the Qur'anic blueprint to align oneself with Divine Order... stick to it in all you do. It is the practical confirmation of proclamations of loving Allah:-

"SAY: IF YOU LOVE ALLAH, THEN FOLLOW ME. ALLAH WILL LOVE YOU
AND FORGIVE YOUR SINS, AND ALLAH IS FORGIVING, MERCIFUL." (3:31)

Rejecting the Sunnah is a rejection of Allah:

"SAY: OBEY ALLAH AND THE MESSENGER, BUT IF THEY TURN BACK, THEN
SURELY ALLAH DOES NOT LOVE THE UNBELIEVERS." (3:32)

Indeed, it is in acceptance and obedience of the Beloved Messenger, Sallallahu alaihi Wasallam, that one can hope to find salvation:-

"AND OBEY ALLAH AND THE MESSENGER, THAT YOU MAY BE SHOWN MERCY." (3:132)