I don’t believe the disciples liked one another very much. Before the cross, they were following Jesus, but they still wanted to “climb the ladder” so they could be the boss over the others in the Kingdom. They were extremely competitive and fought frequently. This was a primary source of their ongoing conflict, “Who’s the greatest?” They wanted a title, a recognized position that gave them the right to have “more say” by virtue of the fact that “I out-rank you.” 
Whenever Jesus addressed this issue with the disciples, He would usually pull a child or a baby out of the crowd as an object lesson. He’d put the child on His lap and tell His power hungry disciples, “You’ll have as much rank as this child. Unless you are willing to become as “rank-less” as a child and a slave you won’t even enter into the Kingdom of heaven.”
Spiritual authority carries no “rank”. It’s is not based on hierarchy, title, or position that entitles you to have “more say” than others. Jesus forbids this kind of system in His Kingdom. Instead, He called people to spiritual authority which functions by the influence of your life based on your willingness to surrender to the Lordship of Jesus Christ, deny yourself, and serve His interests in other people without rank, title, or special privilege.
True spiritual authority looks like people taking the responsibility to serve others in Jesus’ Name. After the disciples went out two-by-two healing the sick and casting out demons, they returned to Jesus with a great multitude of people. When it was time to eat, the disciples wanted to send everyone away, but Jesus rose up and said, “You give them something to eat!” They were looking for authority, but God was requiring them to take responsibility. To walk in authentic spiritual authority, you must become “waiters and waitresses” and surrender all you have to fulfill Jesus’s mission. Instead of giving us a higher rank, Jesus gives us more responsibility, more people to serve. It costs us more time, more work, and what little we had stored up for ourselves. But the power of God follows those who get their eyes off their limitations and surrender to God’s heart to reach the world with His love. As you become like children, you’ll walk like sons.