people guiding others even though they don’t have enough skill or knowledge
—I heard that Joe is teaching the Chinese class. Didn’t he spend only a month in China? Sounds to me like a case of the blind leading the blind.

The Pharisees and teachers of the Jewish law complained that Jesus and his disciples broke the traditions of their ancestors. For example, they asked why Jesus’ followers didn’t wash their hands as a symbol of spiritual cleansing before they ate. Jesus rebuked them, and then told the people that they should not follow the Jewish teachers, saying,

“Listen and understand. What defiles a person is not what goes into the mouth; it is what comes out of the mouth that defiles a person.” Then the disciples came to him and said, “Do you know that when the Pharisees heard this saying they were offended?” And he replied, “Every plant that my heavenly Father did not plant will be uprooted. Leave them! They are blind guides. If someone who is blind leads another who is blind [blind lead the blind], both will fall into a pit.” (Matthew 15:10-14)