How can the word jealous be a good thing and a bad thing at the same time? It all depends on the intent of the heart behind the word.
The Bible is clear on this issue. ”But I say, walk by the Spirit, and you will not gratify the desires of the flesh. For the desires of the flesh are against the Spirit, and the desires of the Spirit are against the flesh, for these are opposed to each other, to keep you from doing the things you want to do. But if you are led by the Spirit, you are not under the law. Now the works of the flesh are evident: sexual immorality, impurity, sensuality, idolatry, sorcery, enmity, strife, jealousy, fits of anger, rivalries, dissensions, divisions, envy, drunkenness, orgies, and things like these. I warn you, as I warned you before, that those who do such things will not inherit the kingdom of God.” (Galatians 5:16-20)
Jealously here is coupled with other examples of our flesh, which is our sin nature, that is, from the eyes of God, evil. These are deliberate choices that we make. It is an example of the corruptness of the flesh which wars against the Spirit of God. A case can be when we are envious of another person because he/she has something that we want and don’t have. Sometimes it is wealth, status, acclamations, abilities, looks and popularity that we want and think we have to have. It becomes, for many, a worship of a false idol. These people are generally not grateful for what God has given them but consumed with what they do not have.
When God says that He is jealous for us, it is a beautiful thing. Concerning the obsession of false idols, God says, “You shall not bow down to them or serve them, for I the Lord your God am a jealous God…” (Exodus 20:5) This kind of jealousy is not because God wants or needs something. It is because God alone is worthy of our worship. We are created in the image of God, and therefore we rightly belong to Him. God loves us and wants us only to have what is good for us. Worshiping God draws us close to Him and builds us up in the way God intends us to go. God wants all of us, not just a piece. God hates whatever it is that draws people away from Him because, in the end, He knows that those things come from Satan whose desire is to kill and destroy.
Is it ever permissible to be jealous over someone? Yes! Our friends, our children, and our faith are a few of the things that God gives us to love and protect. Our children are given to us to raise up as young men and women who love God and love others well. When issues arise that are taking them away from what is best for them, we should be jealous for them and do whatever we can to encourage them to refocus on those things that are right and good. Paul said in 2 Corinthians 11:2, “I am jealous for you with godly jealousy…”