Jesus said, “But you are not to be called rabbi, for you have one teacher, and you are all brothers. And call no man your father on earth, for you have one Father, who is in heaven. Neither be called instructors, for you have one instructor, the Christ. The greatest among you shall be your servant. Whoever exalts himself will be humbled, and whoever humbles himself will be exalted. (Matthew 23:8-12 ESV)

Jesus’ disciples should not try to gain authority over one another as teachers or masters, since Jesus is ultimately each disciple’s teacher and master (you have one teacher … one instructor), to whom the disciple is accountable.