How did they know where to build the Mizbe'ach?
Malbim citing Zevachim 62a: Three Nevi'im ascended with them from Galus. One of them testified about the place of the Mizbe'ach.
What is the connection between fearing Amei ha'Aretz and building the Mizbe'ach?
Rashi: They feared lest Amei ha'Aretz quarrel with them or slander them to the king. They built a Mizbe'ach to offer Olos, so people will hear and know that they did so via the king's command, and they will not quarrel with them about Binyan ha'Bayis.
Ibn Ezra: Due to fear, they prepared a Mizbe'ach to Hashem, so He will help them.
Malbim: This is why they waited and did not offer until the entire nation gathered. When they were few, they feared lest Amei ha'Aretz stop them.
Why is it written va'Ya'al, and we pronounce it va'Ya'alu?
Ibn Ezra: Only one offered - initially, Yehoshua Kohen Gadol offered. We pronounce it va'Ya'alu, for his brethren helped him.
What are "Olos la'Boker vela'Erev"?
Ibn Ezra: Olos proper for morning and evening (Temidim) - they are two [each day].
