the one who always envies someone in society, will never live in gaiety

This idiom means that if a person spends time complaining, criticizing and whining about what everyone else does, owns, or how successful other people are about their financial situation, job career, or results they get, instead of focusing and trying their best to improve one's situation, the only consequence is that this behavior will keep them in the guts, that is, at a lower life level than the one they wish to be.