John 4:35 NKJV - "Do you not say, 'There are still four months and then comes the harvest'? Behold, I say to you, lift up your eyes and look at the fields, for they are already white for harvest!"
What's the significance of "four months?" That's about the amount of time from planting seed to the time when the harvest is ready to be gathered. The normal thought is to plant and water the seed and then wait for the time to harvest.
The context of this verse is the time when Jesus had already spoken to the woman at the well. While she was going back into her city to tell everyone about Jesus, the disciples had just left that city to bring food to Jesus that they had just bought from some of those very same people! Little did the disciples realize just how many of those individuals were already ready to be saved! (Note verses 39-42 where "many" believed on Christ.)
What Jesus wanted His disciples to realize is that though they may plant seeds and have to wait for the seed to bear fruit, there are people who already have had the seed of the Gospel planted in their hearts. They are already "white unto harvest!" That's why Jesus said in verse 38, "I sent you to reap that for which you have not labored; others have labored, and you have entered into their labors." So the word is, "...look at the fields..." All around us are people who have heard the Gospel and they are waiting for someone to gather them in! The woman at the well was looking. The disciples weren't. What about you?
The way Jesus put this to His disciples was a command to obey. If Jesus gives a command you can be sure He will give you the desire and the power to obey it. Trust Him! Think about leading someone to Christ! Wow!