When Jews who deny Christ call on the Lord, they call on a Lord who saves, but on a Lord that doesn't include what Christ did for us. The true God includes Christ.
Do we need to understand the characteristics of the true God when we call on God? For 4,000 years people called on a God that didn't include Christ that they didn't know of, yet God saved the saints. We are told they were brought from their sleep when the curtain split at the time Christ's body died.
Some people have created a God in their minds who is so race conscious that He excluded gentiles from His OT teachings. Is this God they have created truly the one true God?
Gentiles was not excluded in the old testament ,Abraham was a GENTILE & Ruth & Rahab , Neither let the son of the stranger , that hath joined himself to the LORD , speak, saying , The LORD hath utterly separated me from his people: neither let the eunuch say, Behold , I am a dry tree . For thus saith the LORD unto the eunuchs that keep my Sabbaths , and choose the things that plase ME.and take hold of my covenant: Even unto them will I give in mine house and within my walls a place and a name better than of sons and of daughters: I will give them an everlasting name , that shall not be cut off . Isaiah 56:1-8 He also wanted to save the Gential If they would obey ,& keep HIS LAWS . He was NOT only THE GOD of the Jews but also the GOD of GENTILES . GOD bless as HE sees fit .