Why are soul-winners able to recognize tares, when other Christians can't? In thirty-nine years as a born-again Christian, I have been called upon to run "Children's Church" three times.
Shortly out of Bible college, I was in a church that ran about 175 kids in Children's Church, and they put me in charge. Several of us worked hard on bus routes, and we got the attendance up to 300. Then the pastor's wife stepped in, attacking me, slandering me to her followers, and demanding that she be put in charge. Her husband gave it to her, and three years later, they had about ten kids in Children's Church.
In another church, Children's Church was a failure. The woman in charge did nothing, and a handful of high school kids took turns running it. Most of it was play time. I took over, got it going well, and then the woman in charge found out about it. She quickly fired me, put her brother in charge, and abandoned it again. When she left for the mission field a year later, her brother gladly dumped the whole mess on me, and several of us were able to build it into a success.
When I retired to Mexico, our church asked me to start a Children's Church for the four kids in the church. We had a high day of 27, but we averaged around ten or twelve. The entire time, a woman in the church fought me at every step. She went around slandering me, cancelled the Children's Church service a couple of times, started a rival Children's Church service in the front lobby, and urged people not to let their children attend. On one occasion, she put a new Christian in charge, with strict orders not to let me in. She wanted to set up a system in which she would rule over a group of women who would run the Children's Church for her. Later, when a church started by her husband failed, they left Mexico.
In all three cases, a Nicolaitan saw a successful work, and felt that she should rule the people who were doing all the work. In none of those cases did the Nicolaitan contribute to the success of the work. But in all three cases, the Nicolaitan had been involved in Christian service!
Ga 5:19 tells us: Now the works of the flesh are evident, which are:... hatred, contentions, jealousies...selfish ambitions, dissensions...envy...of which I tell you beforehand, just as I also told you in time past, that those who practice such things will not inherit the kingdom of God.
How do soul-winners spot tares? We see them practicing the above sins when they attack us.