What is the Nezer?
'Rashi': It is the crown that David took from Rabas Bnei Amon ? "va'Yikach David Ateres Malkam" (Divrei ha'Yamim I, 20:2). From then and onwards, all Malchei Yehudah wore it.
Radak: It is the royal crown.
What is the Edus?
'Rashi', Rashi (Melachim II, 11:12): It is the Sefer Torah 1 ? "v'Haysah Imo v'Kara Vo Kol Yemei Chayav" (Devarim 17:19).
'Rashi', Rashi (Melachim II, 11:12), both citing Avodah Zarah 44a): The crown is the testimony; everyone [from Beis David] who is proper for kingship, the crown fits him. If he is not proper for kingship, the crown does not fit him.
Radak: It is [the crown and] royal clothing, like "v'Adis Edi" (Yechezkel 23:40). The grammatical form of "Edus" is like "Ge'us." 2
Malbim (Melachim II, 11:12): Really, he needs to write a Sefer Torah after he becomes king; it was given to him at the time [to strengthen his anointment]. It is not clear whether he fulfills the Mitzvah through a Sefer Torah that he commanded to write it while he was a minor.
Radak (from 44a): "Adoniyahu? Misnasei Leimor Ani Emloch" (Melachim I, 1:5) - he tried on the crown, but it did not fit him.
A Navi is needed to anoint a king!
Malbim (Melachim II, 11:12): Zecharyah ben Yehoyada was a Navi.
What is the meaning of "Yechi ha'Melech"?
Refer to Melachim II, 11:12:4:1.
