This refers to the Church, which is the spiritual seed of Abraham, and through which all the peoples on earth are blessed.. It does not refer to anyone -- Jew or gentile -- who rejects Jesus.
Matthew 3:9
And do not think you can say to yourselves, ‘We have Abraham as our father.’ I tell you that out of these stones God can raise up children for Abraham.
John 8:39-44
“Abraham is our father,” they answered.
“If you were Abraham’s children,” said Jesus, “then you would do what Abraham did. As it is, you are looking for a way to kill me, a man who has told you the truth that I heard from God. Abraham did not do such things. You are doing the works of your own father.”
“We are not illegitimate children,” they protested. “The only Father we have is God himself.”
Jesus said to them, “If God were your Father, you would love me, for I have come here from God. I have not come on my own; God sent me. Why is my language not clear to you? Because you are unable to hear what I say. You belong to your father, the devil, and you want to carry out your father’s desires.
Galatians 3:16
The promises were spoken to Abraham and to his seed. Scripture does not say “and to seeds,” meaning many people, but “and to your seed,” meaning one person, who is Christ.
Don’t twist Scripture unless you want to be judged by God. Have a look at Romans 8:29 as a starting point, then 10:1 and 11:26 of the very same epistle.