Does the meaning of the Prophetic Hadith: "Were it not that I would overburden my Ummah, I would have ordered them to use the Siwak with every prayer" imply that the Prophet (peace be upon him) legislates on his own accord, or that he would have commanded it as an obligation were it not for his fear of hardship upon the Ummah?

The Hadith: "Were it not that I would overburden my Ummah, I would have commanded them to use the siwak (tooth-stick) before every prayer" is authentic by agreement of the two Shaykhs (Al-Bukhari and Muslim). The Prophet (peace be upon him) legislates independently because Allah has protected him from error and informed us that he "does not speak out of [personal] inclination." His command for us to obey him indicates that he only legislates what Allah desires. It has been authentically reported that he said: "Indeed, what the Messenger of Allah (peace be upon him) has forbidden is like what Allah has forbidden." It is mentioned in the Quran: "nor do they forbid what Allah and His Messenger have forbidden." There is no dispute among Muslims that the Messenger is infallible in what he conveyed from Allah and in what he legislated for the Ummah. The Ummah has unanimously agreed on his infallibility regarding reporting anything contrary to reality. The Prophet has the right of independent legislation, and examples of this include the prohibition of combining a woman with her paternal aunt or maternal aunt (in marriage). Furthermore, Allah's saying, "And whatever the Messenger gives you, take it," and "Nor does he speak out of [personal] inclination" confirms this.