"Obey Allah and obey the messenger". Quran(64:12)
The Sunnah refers to everything that is said, done or admitted by the Prophet (SAW). For Muslims, their true love is for Prophet Muhammad (SAW) whose entire life is encoded in his Sunnah.
After the Quran, the Sunna is the most important source for deducing Islamic laws in fiqh. There are Quranic verses that, explicitly or implicitly, imply the reliability of the Sunna:
53:3-4: "He the Prophet does not speak out of desire * Indeed it is not except a revelation which is revealed".
59:7: "take what the messenger assigns to you, and abstain from that which he withholds from you".
64:12: "Obey Allah and obey the messenger".
For Muslims following the actions of the Holy Prophet (PBUH) is the matter of meaningful importance because his Sunnah is the source of great benefits for the followers. Believers are encouraged to act in accordance with the Sunnah of the Messenger of Allah.