1)
Why did Shmuel not directly tell Sha'ul's youth to go ahead?
1.
Malbim: It is improper to command someone else's servant.
2)
Where was the youth at the time?
1.
Malbim: He was in back of them.
3)
Why did he say "Amod ka'Yom"?
1.
Radak, Malbim #1: He did not mean 'stay the entire day.' He said (verse 26) "I will send you" and (10:2) "when you go today"! Rather, "ka'Yom" shows the truth of the matter, like "Hishav'ah Li ka'Yom" (Bereishis 25:33). "Amod" - stay until I speak with you.
2.
Malbim: He hinted to him, like it is day now, stand to be king and succeed, like "v'Chis'o cha'Shemesh Negdi" (Tehilim 89:37), "v'Orach Tzadikim ch'Or Nogah" (Mishlei 4:18).
