I am of the view that the practice of Christ lays the foundation for the practice of the church. We are the body of Christ through whom Christ by his imparted Spirit works to continue and complete the ministry he began in incarnate form. So it is essential to consider Jesus' ministry.
Interestingly the accounts of Jesus begin with the witness of the proclaiming prophet John the Baptist who in the prophetic tradition of Israel proclaimed God's impending salvation. There it is again, the divine dabar or logos proclaimed to humanity. He pointed his people to Jesus. That is evangelism. I love his statement; 'I must decrease, he must increase'; that says it all!
Jesus is baptised by John, receives a fresh empowering of the Holy Spirit and is led by the Spirit into the desert to be tested. He wins the battle proclaiming the Word of God to Satan to defeat him.
He then is propelled by the Spirit into ministry. His ministry as I see it involved four dimensions: calling all people to work with him and to community as God intended it, healing the hearts and bodies and restoring to God's community those who came to him with the power of God through word and touch, providing for the poor and needy and preaching the gospel of salvation i.e. the Kingdom (or as John puts it, eternal life).
His intention to preach the gospel as essential to his ministry is seen at the end of Mark 1 where Jesus refused the request to stay in Capernaum after the healing meeting at Peter's mother-in-law's house. Why? Because he had to preach the gospel through the other towns.
He stood in the line of prophets, preaching knowing that his message would harden. He called for repentance and total obedience to God. He called for people to recognise the arrival of the Kingdom and King and to turn from all allegiences to placing first priority of the matters of the Kingdom.
His mission was confined to Israel as he said on several occasions.
Hence evangelism was pivotal to Christ's ministry. We cannot separate it from the other dimensions of calling, healing and providing, but it is pivotal. We cannot separate this proclamation from a whole life as a proclamation i.e. he is not just a preacher of the word, he is the Word, God with us, God made flesh, creator come to his fallen world to save it! But, we cannot downplay this dimension.
His methodology was creative and confrontational. He used parables, a range of simple yet brilliant stories to speak of the love of God and the nature and call of the Kingdom. He challenged those who resisted his ministry directly, calling for them to recognise the coming of God and embrace the King and Kingdom. John tells us more about his proclamation with long discourses in which he used a dynamic array of metaphors to describe himself; all of which called for the Jews to recognise that their Messiah had come (e.g. Vine, Bread of Life, Gate, Shepherd etc).
He encountered people in a deeply personal way, meeting them where they were at. Take Nicodemus in Jn 3, the women at the well in Jn 4, the rich ruler in Mk 10, the woman who anointed his feet in Lk 7 and so on. Each encounter is different. Each calls the person from where they are at relationally to turn to God. I love Mark's editorial note concerning the rich ruler, 'He looked at him and loved him'. For me this is God at work in this world; he looks at us and loves us. Remember this was a bloke who oppressed the poor with his lifestyle! Yet, he is loved!
So Jesus did evangelism and it was I believe the dominant motif of his life. His mission statements in Lk 4:16-20 and 19:10 along with his expressed intentions to preach (e.g. Mk 1:38) and mission summary statements telling us that he preached (e.g. Mt 4; 9) state emphatically that if we are the body of Christ, we are in this business too.
So, if we just work from Jesus' practice and mission self-conception and apply this to our lives today, it is patently clear that we are to preach the gospel as God's people. There is much more to be said though so... wait there's more!