Technically, Sunna refers to the way the Prophet lived. In particular, it refers to the ways and practices he wished Muslims to follow, and to all actions and norms that he lived and recommended but did not make obligatory upon us.
This subject has been dealt with thoroughly by Islamic scholars, all of whom agree that the Sunna is the way of religion, and that it is like a staircase or a ladder to reach the Truth, one of God's Names. It is a way of such merit that all systems and their principles, even those established by scholars and saints, are seen as slight, dim, and obscure beside it. All mystics, spiritual teachers, and truth-seekers have acknowledged and spoken of the Sunna in this way, and thus encouraged everyone to follow it.
God raised the Prophets and through them revealed the proper way of life. He sent Muhammad as His last Prophet; guided him in all his acts; and conveyed fard, wajib, sunna, and mustahab acts,  and even adab (manners). So, one who strives to live as the Prophet did draws closer to God and attains a degree as described in this hadith al-qudsi:
My servants do not draw near to Me with anything more loved by Me than the religious duties I have imposed upon them. They continue to draw near to Me with supererogatory works so that I shall love them. When I love them, I am their hearing with which they hear, their seeing with which they see, their hands with which they grasp, and their feet with which they walk.
One meaning of this is that God enables such believers to see the true reality of things, and so makes it possible for them to evaluate things correctly and efficiently. By opening new gates and new horizons, God leads them to the truth.
Such believers easily take wing and fly toward guidance as they escape from error and corruption. When they hear a voice calling to the truth, they come to themselves, regain enthusiasm, acquire lofty aspirations, make resolutions, and start to prosper morally and spiritually. When they speak, God makes them speak the truth. When they do something, God directs them to good and beneficial results, and never leaves them alone with their self (nafs). Since these servants seek His approval and pleasure, God grants them the opportunities and enables them to act according to His Divine Pleasure.
Therefore, God controlled and guided the lives of all Prophets, blocked all ways except the one leading to His Pleasure, prevented them from choosing ways other than His Own, and directed them to the sole Sunna. So many people have followed the Sunna that it has become the clear road to salvation, the only way free of deviation and leading to success and happiness in this world and the next.
At a time when malice, depravity, and intrigue are so widespread, trying to revive and restore the Sunna, to practice it alongside fard and wajib, to assure its central place in any future society, and to make it endure until the Day of Judgment are actions of the highest importance. Such actions raise those who sincerely work for them to the rank of martyrs and assure them of an equal reward. To gain the rewards of two martyrs would be blessing enough, but more is promised. Further, those who strive to revive the truths of faith may earn rewards far greater than those of 100 martyrs.
Reviving certain elements of the Sunna is particularly worthy of the high rewards promised. For instance, one kind of slanderous gossip is worse than adultery or murder.  There is an obvious difference between slandering an individual and a whole community. In such a case, a personal sin can lead to widespread evil. At a time when Muslims are being invited to depravity, and when Islam's power, influence, and spread are being prevented and undermined, those who strive to restore any aspect of the Sunna will earn the reward of many martyrdoms. If their sincere efforts coincide with the holy days, nights, and months in Islam, their reward may be still greater, for God bestows much more favor upon whom He wills.
Those who serve God are favored and blessed. In their struggle to revive Islamic thought and life at a time when everything is done to oppose Islam, to work for establishing sound institutions with sincere and able staffs, to raise young people's Islamic consciousness—these are parts of a unique task that can be considered a continuance of the Prophet's mission. If such great people and spiritual guides as 'Abd al-Qadir al-Jilani and others appeared, after so many ages, to give moral support, it is because of the great significance and need of the duties to be undertaken.
The Prophet has been seen in dreams watching over, supporting, and giving glad tidings to those on his way. Although no less than a miracle of the Sunna in the service of Sunna, we must not consider such things as recognition of someone's merits and virtues.
Certain individuals, groups, and institutions engaged in this effort surely will obtain a great share of His grace and blessing. This must be so, for "one who caused [an event] is like the doer," and it is another aspect of the vastness of Divine Favor. On the other hand, the responsibility and the trust will be removed from such workers who do not maintain their initial purity, sincerity, enthusiasm, and momentum. Some may be refused, excluded, and even forsaken by Providence, and the trust will be passed to those who are more deserving.
Only if we realize and appreciate God's favor, try to do sincerely whatever we can, and make the best use of the opportunities open to us can we prove ourselves worthy of more and greater favors from God.
 Daylami, 3:116.