Since the creation of the world? Yes. It, however, has not changed in the last ~2000 years. God has had different administrations, or dispensations, for how he has dealt with people throughout history. The way which is person is saved today, is not the same as it was under the law of Moses. In the times of the law of Moses, the way to salvation was faith plus works (keeping the law). Today, in the age of grace, the way to salvation is to have faith in the death, burial and resurrection of the Lord Jesus Christ (1 Corinthians 15:1-4). Nothing more, nothing less. Once a person puts their faith in the finished work of the cross, their salvation is immediately sealed (Ephesians 1:13).