It is not all those claiming to be Christians are Christians. A Christian is a follower of Christ. Those that were called Christians in the Bible were those who were taught in the church about the teachings of Christ. This is according to Acts 11:26. It means you have to learn the doctrines of Christ to be a Christian.
In Matt. 28:20, Jesus commanded his disciples to teach others to observe all the things he had taught them.
One of the guidelines for Christians is in 1Tim. 2:9-10 where Christian women are advised to adorn themselves in modest apparel, with shamefulness and sobriety, not braided hair or gold or costly array.
But, what we see today is women not heeding this advice. It therefore means that many simply call themselves Christians when truly they're not.
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