"He turned to them and said, "O people I have informed you of the message of my Lord and given you sincere advice but you you do not like those who give advice."
The Prophet Salih (upon him peace) was encouraging his people to believe but they refused his sincere advice. This is one of the worst attributes of any person when they refuse to listen to advice. Especially when it comes to elders as many of them have good advice. Its not going to kill you to listen but it does also work both ways as many elders do not listen. So if you hate it when people give you advice then know that you one of the worst characteristics. We need to love of receiving advice if we are true believers.
His rejection made him one of those rejected forever.
Eating too much
This also has a bearing on those who stop lessons of sacred knowledge take place in masjids. They are ignorant and do not see the need for knowledge thus condemning others to the same fate. Any Muslim with a hate for spreading knowledge is not a true Muslim to say the least! As the worst may be feared for such people as the spread of knowledge keeps Islam alive.