‘For if, after they have escaped the defilements of the world through the knowledge of the Lord and Saviour Jesus Christ, they are again entangled in them and overcome, the last state is become worse with them than the first.'
By hearing of Christ and coming to a knowledge of Him and His holy requirements, they have escaped the defilements of the world and its twisted morality. They have come among Christians in order to learn the truth, and as a result of being among them and worshipping with them, their past has dropped off. But let them be warned. If while doing so they simply allow themselves to be entangled again in such defilements and are overcome by them, their last state is worse than the first.
It would seem that these people had not yet come to saving faith in Christ. They were still learning the rudiments on which their faith would be built. They had been impressed by the lives and attitudes of Christians and had come to learn more. But coming from their polytheistic backgrounds it would take time for them to reach a basic understanding of what it was all about. That was why they were so vulnerable.
We tend to forget that while Jews and those familiar with Judaism already had a background which enabled easier understanding of Christian truth, and therefore enabled speedier conversion, out and out pagans had no such background to build on. Even the idea of only one God was new to them and had to be absorbed. And their knowledge of ethics was very distorted. Thus their ‘knowledge of our Lord Jesus Christ' was at a very basic level.
We can compare the problems that missionaries had, and have, before they can be sure that someone has been truly ‘converted'. Often they first have to build up a level of understanding of what sin is, of what God is, and of what God's requirements are, before they can even begin to go on to the deeper truths. Although at times God will surprise them with vessels specially prepared by Him.