GEN1309 [T]he sages tell us that sometimes jealousy can be something very positive and useful.  If an individual recognizes jealous feelings and uses them to build himself up rather than direct the feeling towards the other person, this emotion can indeed be very positive. Pele Yo’etz on “Jealousy.”   Thus, if a person seeks the achievements of a friend and analyzes why that person achieved what he or she did, and then uses that achievement as motivation to better himself or herself, this jealousy is turned outward and becomes a motivator to help a person succeed more.   Therefore, intellectual jealousy among Rabbis is permitted in order to increase Jewish wisdom.   Baba Batra 21a.  The Midrash [Midrash Psalms 37a] explains that if not for this kind of jealousy – i.e. using others’ achievements to motivate to accomplish more – the world as we know it would fall apart. Fewer people would be motivated to build homes, marry, and achieve more in life.   Proverbs tells us not to envy sinners, but rather to be jealous of those that fear the Lord. Proverbs 23:17.   The commentaries explain that a person should not be jealous of any success of evildoers.   Rather, they should envy the accomplishments of the righteous and then try to emulate them.   When Rachel saw that her sister had given birth to many children while she remained barren, the Torah says that Rachel was jealous of her sister [this verse]. But she used that jealousy to improve her own deeds and eventually merit to having children.   Genesis Rabbah 71:6.   AMJV 167