My mom is a Jehovah’s Witness and from what I can understand, their hours of “service” (door-to-door, street corner standing, “Bible” study, etc) are tallied up and I believe they have certain targets - whether these are actually tracked or not, I’m unclear. It seems like she believes the more hours she spends, the better a Witness she is. She seems to be able to handle being ignored and/or having doors slammed in her face, because she has a very strong faith that what she is doing is worthwhile. I believe the attempt is worth almost as much as the result, in their eyes.
I’m a christian, and in all honesty, those sort of street preachers make me cringe. It doesn’t work as a way of introducing someone to the saviour of the world.
But the OP wanted to why people do it. Here are some justifications:
It’s biblical.
John the Baptist went out and preached “repent for the kingdom of heaven is near” (Matt 3:1) - and the people of the time went to the Jordan and got baptised. It didn’t work out for John in the end, but he provides a model - “the voice of one crying in the wilderness, prepare the way for the Lord” (Matt 3:1)
Isaiah 55:11 So shall my word be that goeth forth out of my mouth: it shall not return unto me void, but it shall accomplish that which I please, and it shall prosper in the thing whereto I sent it.
Some christians believe that this means that by speaking Gods word (i.e. quoting the bible) it will accomplish God’s purposes, and so will bring the desired fruit (salvation).
The Parable of the Sower (Matt 13:3-9): The sower scatters the seed (the word of salvation), on the path, amongst the rocks and thorns, and on the good soil, and some bears fruit (people get saved).
Also, in times of revival, it works. The First Great Awakening started the model.
The First Great Awakening resulted from powerful preaching that aimed to convince listeners of their personal guilt and of their need of salvation through decisive action that included public repentance.
Later revivals include stories of people being convicted of their need for salvation by just walking past the churches where revival meetings were being held. Others were saved just by hearing the Word of God being preached. Stories like these often motivate modern street preachers, ignoring the fact that that the culture is not in revival. Christians hope and pray for that time, but it is not happening now.
One of the other issues is that many really fundamental christians try to abstract themselves from the secular world so much, that they find that “friendship evangelism” is problematic because they don’t have much day-to-day contact with non-christians, so street preaching seems a logical alternative.
So here are some of the motivations for street preaching, and there is the other obvious one - the church has it’s share of obsessives and those who are out of touch with reality. But we are forgiven ;).
My own response is to look at the gospels, find that Jesus and the disciples interacted with people and met their needs, often physical rather than spiritual. So I am training to join a group of people who just go out into a town centre on a Friday/Saturday night to be around, help people who need help, and not proselytize unless we get asked a direct question. A better way of introducing people to Jesus by meeting practical needs.
Si
There are also men who will stand on the street and call out sexual propositions to women walking by, and men who will honk their car horns when they spot a woman whom they deem attractive. I have to imagine that this is effective about as often as the street preachers and conversion. I guess hope springs eternal.