Why is Genesis 3:15 often called the first gospel?

Genesis 3:15 appears very early in the biblical story, right after the fall, yet it already introduces the idea that the conflict between good and evil will not end in defeat. There is a promise that the serpent will ultimately be overcome, even though there will be real struggle along the way.

Because of that, many see it as the first hint of redemption. It is not a fully explained message, but it points forward to a future resolution where harm is not the final word.

What makes it meaningful is its placement. Even in the middle of failure and brokenness, the story immediately includes hope. It suggests that restoration was not an afterthought, but part of the unfolding plan from the beginning.

Yes, @ellenvera, it is the basis of the hope and faith that Old Testament believers lived by. We can see that faith in Hebrews 11.