Here are Nouwen's comments in the context of Matthew 20:28 where James and John via their mother ask Jesus for the seats to the left and right of him when his kingdom comes.
"We, like the sons of Zebedee, want to be near power and reflected glory. And if we cannot sit on the throne we at least want to sit very close to it. If we do not dare to ask for this privilege ourselves, we let someone close to us ask for it. Jesus's teaching here is a reminder of our temptation to be like God, and of our resentment for not always being first in line or highly privileged. If we cannot attain the first place, we'll settle for the second place in the kingdom. Those who perceive themselves worthy of first place but have to be content with second place can only look upward with resentment and downard with suspicion. And then, in this competitive and jealous place, neither God nor humanity can be served.
When you cling to your complaints, your heart is full of resentment, and there is no room for God to enter and set you free. Resentment curtails the movement of the Spirit and diminshes the kingdom within. It replaces, faith, hope, and charity with fear, doubt, and rivalry. It makes an enormous difference in our personal and communal lives whether we respond to life in anger and resentment, or in love and gratitude."
This is from the book: Spiritual Formation: Following The Movements of the Spirit
--Henri Nouwen's work with Michael Christensen and Rebecca J. Laird. I highly recommend this book. Thank you to Christensen and Laird for putting these pieces of Nouwen's published and unpublished works and lectures together. We are indebted to you!