The first thing to recognize is that God is the Lord of the harvest. But we are called to labor along with Him. It is Jesus’ desire that you remain in Him and bear much fruit to the glory of God.
Secondly the harvest is now. It is not “four months more and then the harvest.” Instead Jesus wants you to open your eyes and look at the fields. They are ripe for harvest.
Thirdly, the harvest is plentiful. But the workers are few. Therefore Jesus is asking you to ask the Lord of the harvest to send out workers into His harvest field. This is a prayer we need to pray in earnest every day. Remember Jesus is seeing the crowds, harassed and helpless; and He is having compassion on them.
The harvest is for eternal life. This is most important. You are not working for temporal earthly rewards. But instead you are working for souls that bring joy to the heart of God and heaven.
Again, the sower and the reaper, though on many occasions separated by time and distance is working for the same cause. Sometimes a person may do all the labor but the reaping is done by someone else. But each person receives his reward from God because all have one purpose. Both are recognized by God.
Sowing has to precede reaping. Without sowing there is no harvest. You should sow in tears. You should go out weeping carrying seed to sow because the souls of men and women will be lost if you do not sow your seed, the Word of God. Those who do so, it is written, will reap with songs of joy and return with songs of joy carrying sheaves with him. Yes, the harvest will be plentiful.
You should sow your seed in the morning. At the same time you should look for opportunities to sow again in the evening. You should not be idle. Watch out for opportunities.
Paul wrote to Timothy saying: “Preach the Word; be prepared in season and out of season!” Yes, you have to be in an attitude of readiness at all times to sow the Word. When you sow, some seed will fall along the path, some will fall on rocky places, some will fall among thorns. These will not yield any crops. But some seed will fall on good soil and it will produce a crop–“a hundred, sixty or thirty times what was sown.”
Paul also talks about growth: “I planted the seed, Apollos watered it, but God made it grow.” That is why Jesus said the kingdom of God is like a man who scatters seed on the ground. “Night and day, whether he sleeps or gets up, the seed sprouts and grows, though he does not know how.” Then the man puts the sickle to it when it is ready for harvest. So always remember that growth is given by God. Your work is to sow and reap.