Matthew 23:8-12 and Mark 10:35-37
8 "But do not be called Rabbi; for One is your Teacher, and you are all brothers. 9 "Do not call anyone on earth your father; for One is your Father, He who is in heaven. 10 "Do not be called leaders; for One is your Leader, that is, Christ. 11 "But the greatest among you shall be your servant. 12 "Whoever exalts himself shall be humbled; and whoever humbles himself shall be exalted.
Selfish ambition is often exposed by a quest for a title. Titles are sometimes just a matter of practicality, but they are not good when they are a means of prideful position. Jesus said to avoid attitudes that lead to self-promotion, for the one who exalts himself will be humbled. The greatest among His followers shall be a servant. Humble yourself and wait on God for titles and such.
Mark 10:35-37 35 James and John, the two sons of Zebedee, came up to Jesus, saying, "Teacher, we want You to do for us whatever we ask of You." 36 And He said to them, "What do you want Me to do for you?" 37 They said to Him, "Grant that we may sit, one on Your right and one on Your left, in Your glory."
These guys just didn’t get it, they were demanding seats of prestige and honor which, Jesus said, only the Father gives according to His eternal plan. They were certainly selfishly ambitious, and didn’t try to hide it. They lacked Peter’s understanding of humility and ambition.