There must be salvation before training.
There are churches full of people who know all about the Armor or God, fasting, tithing and many other aspects of Christianity. They enjoy the stimulation of meetings and talk about Christian fellowship. Some of these raise hands in "worship."
Before any of these things are taught to a person, he needs to be saved. He needs to know that he needs Jesus and that something has to be done about it. He must not go from information, to being trained to function as a Christian, and he surely should not be given any responsibility in the church.
I have heard well-meaning Christians relate how they got the unsaved to start a quiet time, or recite certain verses about the Promises of God in order to claim them. I have known Christians who were encouraged to exercise spiritual gifts, but were saved years later. Some function as Christians for years and years without ever experiencing the New Birth.
Soldier of The Cross, the Gospel is simple and a man must be born again before he participates in the things of the Lord.
Of course the unsaved should come to church. The Lord can be found there and there should be red-hot ministry to those who come in.
Teaching the unsaved to behave like Christians, think like Christians and speak like Christians, inoculates them against salvation.
Go into all the world and preach the raw, simple, unfettered and powerful Gospel.