Why were the Salvation Army Successful?

The Poor in the Victorian Age
I have no idea where the Salvation Army are today, but when they started, they were Gospel people led by a fiery Gospel man.

William Booth estimated that of the 30 million people living in Victorian England a good 10%, or 3 million, were poor. By poor he did not only mean "no money" - a very limited view of "poverty". The poor were not only materially poor, they were spiritually poor: they were without God and without hope. And Booth understood that it was impossible (and unwise) to separate both kinds of poverty.

In Booth's mind material poverty itself went much further than money: the poor were in every way poor. Crime, homelessness, addiction to alcohol, grime, illness, were all bound up together in this forgotten 10%. He knew that sin and poverty very often go togethe:

"Their vicious habits and destitute circumstances make it certain that, without some kind of extraordinary help, they must hunger and sin, and sin and hunger, until, having multiplied their kind, and filled up the measure of their miseries, the gaunt fingers of death will close upon them and terminate their wretchedness." (all quotes from "In darekest England and the way out")

Can you imagine that truthful - but perfectly politically incorrect - assesment being said by anyone today?

Few people, including the state, were doing anything effective for these desperate and poor people.

What did Booth do?
William Booth called together an army of Christians to help this destitute poor, "Now I propose to go straight for these sinking classes", he declared. He found them homes, found them employment, visited them in their distress and most of all.....

.....shared the Gospel with them. He was convinced that life in Christ was a poor man's only real hope:

"My only hope for the permanent deliverance of mankind from misery, eithe rin this world or the next, is the regeneration or remaking of the individual by the power of thr Holy Spirit though Jesus Christ.." 

Every evening these folk would gather together for 2 hours and sing, hear testimonies and hear short good preaching. EVERY EVENING.

The success of the Salvation Army
There were three reasons why under God the Salvation Army under Booth proved to be so effective.

First, they knew that unless a man is put right with God through Jesus Christ good works are of little long term value to him. Put a drunkard in a nice house, give him a job, and money, and within a few months he'll be back in the gutter. Only the Gospel can change a man's life (starting on the inside).

Second, Booth knew that caring for a man's material needs paved the way for him being opened to the Gospel. The practical help given was never an end in itself but always a means to an end, that these people would be able to hear of the love of Jesus Christ.

Third, Booth shared the Gospel with them EVERY DAY. This is how lives are transformed, not by once a week, but by every single day being among God's people, hearing God's word.

So, in the end, Booth's Salvation Army turned out Christians: and that was the key to his success, nothing more, nothing less.