In these days he went out to the mountain to pray, and all night he continued in prayer to God. And when day came, he called his disciples and chose from them twelve, whom he named apostles:
Jesus chose twelve men from among all His disciples to represent His teaching and ministry to the world. After His ascension, these same men would be tasked with proclaiming His saving gospel to the world. He would take from among His followers a dozen men who would become leaders. It was necessary so that Jesus' teaching would continue forward once He went back to His Father.
Jesus only walked among us for 33 years or so. His public ministry of teaching and healing only lasted for around 3 of those years. That's roughly 36 months. That is a ridiculously "fast" ministry and a short time to change the world given the scope of human history. It's a mote of dust on the scale of human time. In that short burst of God-work, Jesus had to prepare a dozen men to give the entirety of the rest of their lives to the message and work that He came to do. Jesus' most important investment of ministry and His legacy would require these men lead with all that they had. Their ministry would eclipse His own in some ways. That's why He told them they would do "greater works". And they did it! The church has continued what Jesus began. And because Jesus developed these twelve apostles, the church has now continued these two millennia with the gospel as our reason to exist. This is despite every kind of persecution and resistance possible.
No wonder Jesus lost a night's sleep. He invested that precious time in prayerful communion with the Father before commissioning His twelve apostles. The entire future of everything, the success of the gospel message and the building of Christ's church rested on the commitment of twelve apostles sent by Jesus. These were key leaders. They would incalculably multiply His ministry. Investing leadership time with these twelve was vital to the gospel doing what God intended. The message needed passionate, gifted, trained, strong messengers.
Developing Christian leaders is still very important and needful work. It must be done. The gospel is still the world's most needed truth. It is information and salvation that all people everywhere need. And it advances in the lives of obedient disciples and skilled leaders.