verses 36-38, Jesus is saying that he sees that these people in the crowd are lost and have been failed by the leaders in Israel. When he looks into the crowd he sees that there are many people who are ready to follow Jesus but still there is not enough (The harvest - work of God - is plentiful but the labour - people - is few). He says in verse 38 to the crowd that to get more labourers they should pray to God to bring more people to spread the word.