1)
What did he see?
1.
Rashi: He saw the enemy coming. Malbim ? Nechemyah was the lookout.
2)
Why did he rise?
1.
Rashi: To speak to the Sarim, to invigorate them to fight the enemy.
2.
Malbim: He warned the people that the battle is coming, and they should not fear. They should remember Hashem, and fight.
3)
Why did he say "Al Acheichem"?
1.
Rashi: He means, for the sake of your brothers.
