2 Samuel 19:43
‘But the men of Israel answered the men of Judah and said, “We have ten parts in the king, therefore we also have more claim on David than you. Why then did you treat us with contempt? Was it not our advice first to bring back our king?” Yet the words of the men of Judah were harsher than the words of the men of Israel.’
Jealousy is a real thing. Especially in families. While these aren't immediate families, the are distantly related. The bible acknowledges this in Proverbs 17:17, "A friend loves at all times, And a brother is born for adversity." It doesn't say it's right, but that it's not uncommon for families to have sibling issues.
At some point we need to choose not to be bothered with jealousy. Jesus shared it with the christian creed, 'Then Jesus said His to disciples, "If anyone desires to come after Me, let him deny himself, and take up his cross, and follow Me."' As children we needed to be taught to not be selfish. We learn to function at an acceptable level. However, there is an undercurrent of selfishness. God targets that and weeds it out.
Jesus went further than to let others go first, but to love them. There's a difference between denying self and loving others. "The second is like it, ‘YOU SHALL LOVE YOUR NEIGHBOR AS YOURSELF’", (Matthew 22:39). Jesus called this the second commandment. In a sense, there is very freeing. We don't need to worry about our agenda. God's got it. It gives us a new agenda, love.
This doesn't mean loving others will be easy. God will bring others that need love, often the unlovable. He will give us the love to do so. God will allow us to be stretched. That is awesome how much He loves us all.
Back to the topic of jealousy. It can creep up. All of us have vulnerable areas. Surrender them to Him. Ecclesiastes 3:11a says, "He makes all things beautiful in its time." Selfishness and hatred are not attractive. We all have it. He will work on it and turn it into love and service to others.
Jealousy can be a good thing. Exodus 34:14 says, "For you must not worship any other god, for the LORD, whose name is Jealous, is a jealous God." We can't have divided loyalty. He alone is to be our God. We can be jealous for others, if they are being treated poorly.
God, You are so amazing. Thank You for rooting out self ambition and selfishness and replacing it with love. I don't have to worry about going first. No more jealousy.