Today is not "the beginning" and the gospel was always for all the descendants of Eve that's what God said to Eve on the day she first sinned.
Genesis 3:
8And they heard the voice of Jehovah God walking in the garden in the cool of the day: and the man and his wife hid themselves from the presence of Jehovah God amongst the trees of the garden.
9And Jehovah God called unto the man, and said unto him, Where art thou?
10And he said, I heard thy voice in the garden, and I was afraid, because I was naked; and I hid myself.
11And he said, Who told thee that thou wast naked? Hast thou eaten of the tree, whereof I commanded thee that thou shouldest not eat?
12And the man said, The woman whom thou gavest to be with me, she gave me of the tree, and I did eat.
13And Jehovah God said unto the woman, What is this thou hast done? And the woman said, The serpent beguiled me, and I did eat.
14And Jehovah God said unto the serpent, Because thou hast done this, cursed art thou above all cattle, and above every beast of the field; upon thy belly shalt thou go, and dust shalt thou eat all the days of thy life:
15and I will put enmity between thee and the woman, and between thy seed and her seed: he shall bruise thy head, and thou shalt bruise his heel.
And Abraham received a covenant for the blessing of all the nations
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