No one is indispensable in Christ's church. God's work can easily carry on without us. In fact, it can carry on much better without the help of those conceited folk who consider themselves indispensable! We must recognize this fact constantly. I once read of a prescription to humble the soul of anyone who considered himself "indispensable"! It was suggested that he fill a bucket with water and put his hand in it up to his wrist - and then pull it out. The hole that remains in the water will be a measure of how much he will be missed when he is gone!! Our gifts are useful to the church; but no-one is indispensable.
We must be willing to withdraw into the background anytime God calls us to. But the self-centered Christian worker will never accept that. He will want to hold on to his position for as long as possible. Many such "Christian leaders" are rotting away on their "thrones" today, hindering the work of God. They do not know what it is to fade graciously into the background and let someone else take their place.
You've probably heard the saying that success without a successor is a failure. Jesus recognized this and trained people to carry on His work. In 3½ years He had trained others to take over the leadership of His work. What an example for us to follow!
Paul recognized the necessity of training other people to carry on the work. In 2 Timothy 2:2, he told Timothy, "What I have committed to you, I want you to pass on to other people who will in turn be able to train others (the fourth generation)" (Paraphrase). What Paul was saying in effect was, "You must ensure that you commit this treasure to others. Don't ever hinder people younger than you, from coming up." Even businessmen recognize the principle that "success without a successor is a failure". But many Christian leaders haven't recognized it. Truly, "the children of this world are in their generation wiser than the children of light."
It is indeed nothing but self-centeredness that makes a man jealous of someone younger who can do things better than he can. Cain was jealous of the fact that God had accepted Abel but rejected him. If Abel had been older than him, that might have been tolerable. But it was the awful fact that his younger brother was better than him that made him furious enough to slay Abel.
We see the same in the case of Joseph and his brothers. Joseph received divine revelations, and that made all his ten older brothers green with jealousy - so jealous that they wanted to kill him.
King Saul was jealous of young David, because the women sang, "Saul has slain thousands while David has slain ten thousands." From that day he determined to kill him. Man's history - and alas, the history of the Christian church too - is filled with the same story over and over again.
Likewise, the elderly Pharisees were jealous of the popularity of the young Jesus of Nazareth and determined to get him crucified, at any cost.
On the other hand, what a refreshing contrast it is to look at a man like Barnabas in the New Testament. He was a senior worker who took the newly-converted Paul under his wing, when no one else would accept Paul. Barnabas brought him to the church in Antioch and encouraged him. In Acts chapter 13, we read that Barnabas and Paul went out together on a missionary journey. And when Barnabas saw that God was calling this junior worker, Paul, to a larger ministry than his own, he willingly stepped back and graciously faded into the background. And the phrase, "Barnabas and Paul", changes almost unnoticed to "Paul and Barnabas" in the book of Acts. The Christian church suffers today, because there are few like Barnabas who know what it is to step back and let another be honored. We are willing to step back in matters of no importance. When passing through a door, for example, we don't mind stepping back and permitting another to go through first. But in the things that matter - such as position and leadership in the Christian church - we are not so ready to step back. Our self-life is so deceitful. We can have a false humility in things that don't count. But it is in important matters that we see ourselves as we really are.