If you want to be a miserable person, then be an envious person. It is not necessarily a bad thing to admire something that someone else has. When we say, "I envy you. You are going on vacation," we aren't necessarily using envy
in the worst sense of the word.
To envy is to be angry when someone else has something that you don't have. A literal definition of the word envy
is "a malignant or hostile feeling." So it is not a matter of saying, "You have a lot. Wow, that is really great! I wish I had that!"
Rather, it's an attitude that says, I am actually angry with you that you have those things and I don't have them.
Envy has been described as a small-town sin; it breeds on proximity. We don't tend to envy someone who is famous and successful. Instead, we envy our neighbors, a relative, or a coworker. We are fine as long as we are all equal, as long as we are all on the same playing field. But if one begins to succeed, if one gets an opportunity we think we should have had, if one has something wonderful happen, we become envious.
We don't know exactly what caused Cain to murder his brother Abel, but I think it is safe to say that envy and jealousy played a part. Abel's sacrifice was accepted, and Cain's was not. Envy unchecked can become a major problem, and Cain's envy led to murder. Cain was not mastered by God, so he became enslaved by the Devil.
Shakespeare called envy the green-eyed monster, and it's a green-eyed monster that can strangle you. Be a jealous person, and you will give the Devil a foothold just as Cain did—and you will face the repercussions.