Your claim that some were once upon a time saved by works is Satanic.
That is a horrific thing to say about something you obviously don't understand.
Read this scripture:
Hebrews 9:22
According to the Law, in fact, nearly everything must be purified with blood, and without the shedding of blood
there is no forgiveness.
Did you read that?
That is about the shedding of ANIMAL BLOOD so the Jews could have forgiven from God for their sins.
Do you know what atonement means?
Leviticus 17:11 For the life of the flesh is in the blood: and I have given it to you upon the altar
to make an atonement for your souls: for it is the blood that makes an atonement for the soul.
Did you read that?
Now do you want to be more careful about what you say about things you obviously don't know much about?
Read this scripture:
Romans 9:4 the people of Israel.
Theirs is the adoption as sons; theirs the divine glory and the covenants; theirs the giving of the Law, the temple worship, and the promises. 5 Theirs are the patriarchs, and from them proceeds the human descent of Christ, who is God over all, forever worthy of praise! Amen.
Did you read how the Jews were the adoption of sons? Do you really think that God would adopt them if they did not obey the ceremonial works?
Read this scripture:
Colossians 2:13 When you were dead in your sins and in the uncircumcision of your flesh, God made you alive with Christ. He forgave us all our sins,
The Jews were not dead in their sins like the Gentiles were because the Jews obeyed God and got circumcised.
A person is saved by believing and obeying God. God is the one who said to do the ceremonial works.