What did God immediately do after realizing He had lost the human race?

After realizing He had lost the human race, God immediately set in motion a plan of redemption through the seed of the woman (Genesis 3:15). He began the process of buying back the whole human race, though centuries passed before it became a reality through Christ Jesus.

Les explains that redemption means paying a price for something that was once yours and you lost it. That is exactly what happened to the human race: it was God's in the person of Adam and Eve, but He lost it when they sinned. As soon as He realized He had lost it, as shown in Genesis 3:15, He immediately kicked into gear a plan of redemption through the seed of the woman. It took centuries before it became a reality, but it all began right after Adam and Eve sinned. He put in motion the plan of buying back the whole human race. Paul teaches this in Romans 3, pointing to Christ Jesus as the propitiation through faith in His blood.

Genesis 3:15

And I will put enmity between thee and the woman, and between thy seed and her seed; it shall bruise thy head, and thou shalt bruise his heel.

What did God do as soon as Adam and Eve sinned and He lost the human race?

As soon as Adam and Eve sinned and God lost the human race, He immediately put into motion a plan of redemption through the seed of the woman. It began right then, though centuries passed before it became reality, and it was His plan of buying back the whole human race.