Ahab one day looks out and suddenly has a desire for Naboth's vineyard. Life was not going well for the King and he was depressed. When we become tired by life we become susceptible to temptation. Ahab nows wants Naboth's garden. It will make him feel better about himself.
So Ahab tries to negotiate for the vineyard. Naboth says "No!". The reason was that Naboth was following the Word of God. Leviticus 25:23 - ‘The land, moreover, shall not be sold permanently, for the land is Mine; for you are but aliens and sojourners with Me." There are something in life that we cannot have. No amount of money or power gives us the right to them. Ahab eventually allows his desires to overwhelm doing what is right.
This is a pivotal turning point to the complete and total downfall of the King of Israel. Elijah will come soon and speak a final word of judgment from God.
It took just one tired and frustrated day to lead to the final fall of a king! Beware that you are most susceptible to evil on days when you are the most tired by life.