King Noah did not do things the way his father did. He probably considered his father was too "old school" and decided to make things they way he wanted them. Either he didn't understand or didn't want to listen to his father's counsels about trusting in the Lord.
King Noah's first order of business was to tax the people (Mosiah 11:3) so that he could support his wickedness. With those taxes (which was a double tithe) he supported himself, his concubines, wives, priests and their wives and concubines (v. 4). He dismissed the priests his father called and placed new ones in their stead (v. 5). He built spacious buildings and decorated them with gold, silver, iron, brass, ziff and copper (v.8). He built two towers so he could overlook his kingdom as well as that of the Lamanites (v. 12-13). He had vineyards planted so that he could drink wine (v. 15). And when the Lamanites attacked them again, he sent an army to drive them back. And when the army returned, instead returning to their fields and flocks, they boasted and delighted in bloodshed (v. 19).
In sum, King Noah was a very wicked man and caused his people to grow in wickedness.
Abinadi did not mince his words. He gave it to them straight and undiluted. He made it know in no uncertain conditions that they were wicked, that the Lord was not pleased with their wickedness and that if they did not repent, they would suffer greatly.
He specifically tells them that they will be delivered "into the hands of their enemies" if they did not repent (v. 21). This admonition must have made their mighty men laugh because their fifty could stand against thousands of Lamanites (v. 19). But in not too many years, this prophecy was fulfilled.
He specifically tells them that they would be brought into bondage and they none would deliver them except the Lord their God (v. 23). They must have thought this warning was ridiculous because they've delivered themselves many times out of their enemies' hands. But in not too many years, this prophecy was fulfilled.
He specifically tells them that the Lord would be slow to hear their prayers (v. 25). This prophecy too would be fulfilled.
The people sought to take away his life, "but the Lord delivered him out of their hands" (v. 26).
Soon, King Noah heard of Abinadi and he commanded that Abinadi be slain because he was causing contentions among his people (v. 28). This was King Noah's way of trying to silence his critic(s).
Abinadi went into hiding for two years only to re-emerge and begin prophesying the same thing as he did before.
Follow the Prophet
What is one message we can take from Mosiah 11? We would be smart to remember that when the prophet speaks, we ought to listen and heed his warnings and counsels. One of the purposes of the scriptures is to demonstrate the consequences of people who fail to listen to a prophet. The scriptures also demonstrate the blessings of those who do follow the counsels of a prophet.
This chapter is no different. It is plainly evident that all the things Abinadi spoke came to pass.