Why did he ask about one particular grave?
Rashi: He saw thorns on one side, and myrtle and fragrances on the other side. This astounded him, so he asked about it. Radak - they told him that a Tzadik and Rasha were buried there - a true Navi and a false Navi.
Radak: The old [false] Navi asked his sons to make a big marker on his grave, so it will be distinguished from the others. He knew that the Navi's prophecy will be fulfilled; he said "Ki Hayah Yihyeh ha'Davar" (Melachim I, 13:32). He knew that the bones of the true Navi will not be taken out.
How did the people of the city know? This was more than 300 years [after the true Navi died]!
Radak: They had a tradition, son from father.
Why does it say "ha'Kever Ish ha'Elokim"?
Radak: The word Samuch [to Ish] is omitted. It should say ha'Kever Kever Ish ha'Elokim. Also "ha'Aron ha'Bris" (Yehoshua 3:14) [is like ha'Aron Aron ha'Bris].
Was only the Ish ha'Elokim from Yehudah buried there?
Rashi: No, also the Navi Sheker commanded his sons to bury him next to the Navi Emes (in the same grave).
Why does it say "ha'Mizbe'ach Beis Kel" with the prefix Hei ha'Yedi'ah (to identify)? It is Samuch!
Radak: This is exceptional; there are other such cases, e.g. "ha'Lishkos ha'Kodesh" (Yechezkel 46:19), "ha'Ysad ha'Ereg" (Shoftim 16:14) and similar verses.
