“When he went out after this, he noticed a tax collector, Levi by name, sitting at the tax office, and said to him, ‘Follow me.’
And leaving everything Levi got up and followed him. In his honour Levi held a great reception in his house, and with them at table was a large gathering of tax collectors and others. The Pharisees and their scribes complained to his disciples and said, ‘Why do you eat and drink with tax collectors and sinners?’
Jesus said to them in reply, ‘It is not those that are well who need the doctor, but the sick. I have come to call not the upright but sinners to repentance.'”
Jesus calls everyone to follow Him, but in the Gospels we see Him pointing out specific people and presents them with the choice very directly. Apparently, He does not need to have to interact much with people before asking – telling, even – them.. He sees the tax collector at work, and knows enough. This is a man He wants to be seen with.
The world doesn’t understand that, as we see in the reaction of the Pharisees. Why choose to be with these people, these sinners who are spat out by the rest of decent society? But dividing society in wanted and unwanted people is an artificial construct. After all, society is made up by all people, rich and poor, holy and sinful, good and evil. Jesus choose to become a part of this multifaceted society in order to heal it. And just like when our body is sick, we try to heal the parts that affect us adversely, not cut them off. Jesus does the same. He does not cut out the unwanted elements of society, but tries to change them for the better.
Human society, the combined body of all our interactions and relations is not an accident. It flows from our nature as human beings created by God. And as such it is wanted and has a purpose or destination in God. Christ came to put us on the right path to that destination, by healing us from our sins and ills. And he does so first in the ways of society: in the form of a social gathering. He eats and drinks with the tax collectors. We can only imagine what they talked about, but it would be a safe bet to assume that Jesus won Himself a place in the hearts of the sinners He ate with.
We are called to imitate Jesus and introduce Him to the people around us. A good way to start is simply through society, as Jesus did. Not by expounding about the evilness of their ways or pouring boatloads of information about God and faith on them. That can wait, and will come naturally when the time, and everyone involved, is ready. That is the start of evangelisation.