Most of the time, jealousy is not a good thing to witness. Jealous people seem to feel bad about themselves, so they see others as rivals. If someone is jealous of you, realize that they may be threatened by you. God’s jealousy for us is a good thing. He claims us as His own and He wants the best for us. Just as God wants the best for us, we should want the best for others.
Exodus 20:5-6 (ESV)
5 You shall not bow down to them or serve them, for I the LORD your God am a jealous God, visiting the iniquity of the fathers on the children to the third and the fourth generation of those who hate me,
6 but showing steadfast love to thousands of those who love me and keep my commandments.