1)
Why did he say to take 30 men?
1.
Rashi: Because their strength waned due to hunger, all of them were needed [to lift him from the deep pit].
2.
Malbim: The king withdrew from the matter and said "he is in your hands" (verse 5). The guards could protest against Kushi [trying to raise Yirmeyah]. He told him to take 30 men, to take him by force.
