The Bible is replete with examples of real people living real lives. Since the Bible people are real people, AKA sinners, they sin. The Bible doesn't shy away from showing that.
In thinking over some of the more famous cases of bad acts, the brotherly jealousy/sibling rivalry issue formed in my mind. It happened a lot.
Cain, jealous over God favoring his brother Abel's sacrifice more than his own, he slew Abel. (Genesis 4:4, 8).
Happy little Joseph awoke one day and told his brothers an amazing dream he'd had. (Genesis 37:4-5). The brothers hated Joseph because their father favored Joseph. When Joseph told the brothers his dream, one that showed how he'd rule over them one day, the brothers were jealous of him all the more. (Genesis 37:11, Acts 7:9). Then they plotted to kill him. (But God intervened and providentially saved Joseph).
David and his brothers. We read of that whole process where prophet Samuel comes to David's father asking him to assemble all the sons. (1 Samuel 16). He is going to anoint a new king. The sons must have felt great excitement! One by one, though, they were rejected. Only after little David was brought in from the fields, too young and small to even be considered in the original lineup, were the halted proceedings resumed. In front of the father and brothers, Saul, on behalf of God, anointed David.
After that, the brothers were in the encampment awaiting the day when someone, anyone, would come forward to slay Goliath the Philistine. Errand-boy David arrived with provisions for the brothers, but was angrily mocked and scorned instead. What had David done to merit such treatment? He'd spoken up against Goliath.
And David said to the men who stood by him, "What shall be done for the man who kills this Philistine and takes away the reproach from Israel? For who is this uncircumcised Philistine, that he should defy the armies of the living God? (1 Samuel 17:26)
His brother Eliab heard and became angry. Presumably he was embarrassed. I mean, it had been 40 days of listening to Goliath taunt them and not one Israelite had stood up to fight. Not one. Certainly not Eliab. Then comes little David and he makes a bold statement immediately.
Now Eliab his eldest brother heard when he spoke to the men. And Eliab's anger was kindled against David, and he said, "Why have you come down? And with whom have you left those few sheep in the wilderness? I know your presumption and the evil of your heart, for you have come down to see the battle." (1 Samuel 17:28).
The jealousy between Jacob and Esau is well documented. Esau was favored by the father, Jacob by the mother. Instead of enjoying this unique relationship, mother and son plotted to get an upper hand. Esau helped by throwing away his birthright for a bowl of soup. Then Jacob tricks father and brother into gaining the blessing. Thus began a decades-long separation due to anger and rivalry.
Then I saw that all toil and all skill in work come from a man's envy of his neighbor. This also is vanity and a striving after wind. (Ecclesiastes 4:4)
Being jealous of another is a sin. And please don't cite "God is jealous so I can be, too". God's jealousy is for us, not against us. His perfection makes His jealousy righteous.
God’s jealousy is always a product of his perfect, self-sufficient love (Exodus 3:14; Psalm 50:9–15; Isaiah 40:28), which provides the opportunity for him to feel deeply jealous about the people with which he has freely covenanted. SourceHow to overcome this sinful emotion?
Here is an article from Desiring God about jealousy (also quoted above). Hey, Jealousy
Here is a one-minute audio from Grace To You's 'Portrait of Grace' series, Overcoming Jealousy
What Does the Bible Say about Jealousy?
