The term "Christian" is a title that was originally given to us by the world. Notice, the believers were "called Christians first in Antioch." These believers spoke so frequently and affectionately of Christ that the world coined the term Christians. Of course, they meant it in a derogatory sense. The citizens of Antioch were famous for their witty quips; they were the punsters of their day. Since this expression has a Latin origin, it was probably the Romans among them who first assigned this name to believers.
Be that as it may, we have no major objection to believers being called Christians, based on Acts 11:26; 26:28, and I Peter 4:16. Today, however, the word is so sweeping that it includes both believers and religious unbelievers. While a true believer is a Christian, one who calls himself a Christian may not necessarily be saved. With that said, we prefer the terminology "believer," "saved," "brethren," "saints," or "faithful in Christ Jesus." We would also include the designation "grace believers," the sense of which is drawn from Paul's letters, but it should be remembered that not all believers are "grace" as we understand the usage.