If this were so then the sacrifice of Jesus would not have been necessary.
I see that scripture is clear, those who believed God before the resurrection were accredited with righteousness, even though they had not obtained the promise, those after the resurrection were made righteous through the blood of Jesus and obtained the promise. So Jesus after his death descended to those who were in the bosom of Abraham and brought freedom to them.
As well consider Saul, the Spirit would come upon him one minute and he would prophecy, and the next minute Satan would enter him and he would try to kill David.
John 20 makes clear when the apostles were born again into the New Covenant.
22 And when he had said this, He breathed on them and said to them, “Receive the Holy Spirit.
Was Thomas saved? He didn't believe until he saw,