We all want fair and equal treatment. From childhood when we first say, "Hey, that's not fair!" to adulthood, "I have my rights, you know!" we are looking for equality.
The disciples had this problem from time to time. As Jesus was explaining how the Kingdom of God works, he told the parable of the workers in the vineyard. The owner of the vineyard throughout the day hired men to work. By the end of the day, some had worked only an hour, but every man was paid the same. The men who had worked all day complained that this was unfair. But the owner made clear that his intent was not to be unfair, but to be generous. He goes as far as accusing the first hired of jealousy. (Matthew 20:1-16)
Sometimes it's hard to feel generous. Sometimes jealousy is much easier. It's a form of greed. We want, we want, we want. How much is enough? Jealousy and greed try to convince us that it is never enough.
But the Bible tells us that Jesus is enough, He is sufficient (2nd Corinthians 12:9). We don't need anything else. Jesus did it all, said it all, sacrificed all. Jealousy and greed will just have to take a back seat.