Why does it say "va'Ya'amidu Davar"?
Malbim: This was due to Rava's concern, lest people belittle the Isur of Chametz during Pesach 1 . Because Chachamim disagreed, the king and officers established the matter.
Sanhedrin 12b: If we already started teaching laws of Pesach, and we are Me'aber the year, when people hear that Pesach was delayed, they will belittle the Isur of Chametz!
Why does it say "mi'Be'er Sheva v'Ad Dan"?
'Rashi': This is the extent of the 10 tribes.
What is the meaning of "Lo la'Rov Asu ka'Kasuv"?
'Rashi': Many years passed that they did not do it properly.
Redak (2): Until now, most of Yisrael did not do [Pesach], for they were idolaters. They were not concerned to come to Yerushalayim to serve Hashem. Chizkiyah sent messengers, but most mocked them. Even those who came, not all became Tahor; they ate Pesach b'Tum'ah, and Chizkiyah needed to pray for them (18). Therefore, they needed to add a month 1 .
Malbim: If they would not add a month to the year, Pesach Rishon would be b'Tum'ah, and a small number of Yisraelim gathered. He thought that they are the minority of Yisrael. The minority may not offer Pesach b'Tum'ah! Chachamim disagreed, for we consider the majority of Yisrael in the Azarah 2 , even if they are the minority of Yisrael. Therefore, he should not have been Me'aber due to Tum'ah.
