"I ride my bicycle because it is efficient" says one. "Wonderful!" replies the Master, "Your path will be smooth and easy."
"I ride my bicycle because it is good for my health" says the second. "Wonderful!" replies the Master, "You will live a long and healthy life."
"I ride my bicycle to ride my bicycle" says the third. "I am your student!" declares the Master.
So, if I read this correctly, the moral of this parable is that...
The first student then went on to follow a smooth and easy path.
The second student then went on to live a long and happy life.
The third student then went on to have an old man follow him around asking him questions every five minutes.