In John chapter 4 we see Jesus get into an evangelistic conversation with a Samaritan woman. The woman’s life is greatly impacted and as a result many other Samaritans are become believers in Christ (John 4:39). There is a kingdom domino effect that took place through Jesus evangelizing this one Samaritan woman. And in the middle of this work that Jesus is doing his disciples come up to him and urge him to eat something assuming that he must be hungry and this is the response of Jesus:
34 Jesus said to them, “My food is to do the will of him who sent me and to accomplish his work. 35 Do you not say, ‘There are yet four months, then comes the harvest’? Look, I tell you, lift up your eyes, and see that the fields are white for harvest. 36 Already the one who reaps is receiving wages and gathering fruit for eternal life, so that sower and reaper may rejoice together. 37 For here the saying holds true, ‘One sows and another reaps.’ 38 I sent you to reap that for which you did not labor. Others have labored, and you have entered into their labor.” John 4:34-38 ESV
Here are a few things we can learn from the evangelistic work & words of Christ here in this passage of Scripture:

Evangelism is the will of God.

It is God’s will for every Christian to be involved in the work of evangelism. Jesus said that this is one of the reasons he came (Mark 1:38). And Jesus described the will of God as food. What does food do? It gives nourishment, pleasure and sense of being satisfied. This is what the Christian should experience in doing the will of God because we are fashioned and designed for the will of God much like God designed food for the human body. There have been numerous times that I have engaged in an evangelistic conversation about God and before that I was having a mediocre day and after sharing the gospel with someone my day turned into a great day, marked with sense of purpose and excitement. Sharing the gospel with people shouldn’t be merely a duty for the Christian it should be a great delight, something that we are eager and ready to do on a daily basis. Sometimes it just takes one or two good experiences in evangelism to get you hooked. Much like it may have been for you when you discovered your favorite restaurant. You went and tasted the food and now you’re sold on going back there (if your budget permits). John tells us before Jesus even had that encounter with the Samaritan woman that Jesus “had to pass through Samaria” (John 4:4). It seems that John is giving us some insight here as to God the Father directing the steps of his Son. The Net Bible commentary notes says this about that statement: “Although some take the impersonal verb had to (δεῖ, dei) here to indicate logical necessity only, normally in John’s Gospel its use involves God’s will or plan (3:7, 3:14, 3:30, 4:4, 4:20, 4:24, 9:4, 10:16, 12:34, 20:9)”. It is God’s will and God’s plan for you to share the gospel with others.

Evangelism can seem awkward & feel uncomfortable.

Jesus was sold out to the will of God and was willing to press through any barriers that might get in the way of him doing his Father’s will. And in the context of John 4 we see him so committed to doing the will of God that he was willing to talk to a Samaritan woman. First of all Jews didn’t spend much time having any peaceful conversations with Samaritans. There was much hostility between the two groups. Secondly, Jesus was a male Jewish Rabbi speaking with an immoral Samaritan woman. If Jesus was concerned about image before man he wouldn’t have been talking with this woman, even the disciples of Jesus marveled and questioned why he was talking with this Samaritan woman. Evangelism will require you to get out of your comfort zone and let go of how you want to be perceived by people. Jesus took the risk of being viewed as an ungodly sinner by spending time with such people as tax collectors, sinners and this Samaritan woman. So much so that he gained the reputation of being a “friend of sinners”. Would that be said about you? Are you willing to befriend sinners in order that you might win them to Christ?

Evangelism is to be done through conversation not just giving a presentation.

Jesus initiated and engaged in a conversation with this woman who was even surprised herself that Jesus would talk to her. The conversation started around a common interest, namely water and then Jesus directed the conversation from the natural to the spiritual, that is “living water”, which is what the Samaritan woman really needed. She had sought fulfillment through immoral relationships in which Jesus seemed to prophetically call her out on. Remember to address the issue of sin when you are evangelizing and don’t beat around the bush being afraid to talk about sin. Jesus talked about it and he called people to repentance of their sin. Evangelism is incomplete if you don’t address sin and the need for repentance. And most important of all, talk about Jesus the Messiah, the Savior, the one who saves His people from their sins. Talk about the eternal life that he provides through faith in him. Talk about the reality that he is the only one who can satisfy the deepest longings of the soul (John 6:35), because we are created from Him, to know Him and be known by Him, to love Him and be loved by Him.