When did God begin to treat the Israelites as His chosen nation?

God began to treat the Israelites as His chosen, set apart nation immediately after Jacob's twelve sons ended up down in Egypt. At that point He started dealing with them as His chosen people, before bringing them out supernaturally under Moses' leadership through miracle after miracle.

Les explains that God supernaturally brought about the nation of Israel by calling Abraham out of Ur of the Chaldees and promising to make of him a nation of people. That promise was fulfilled with the supernatural birth of Isaac. Isaac fathered Jacob, Jacob fathered the twelve sons, and they ended up down in Egypt. Immediately God began to deal with those Israelites as His chosen, set apart nation. He then brought them out supernaturally, with miracle after miracle, and that multitude followed Moses.

How did the Israelites become God's chosen, set-apart nation?

God supernaturally formed Israel by calling Abraham out of Ur of the Chaldees, promising to make him a nation, and fulfilling that promise through Isaac's supernatural birth. Through Jacob's twelve sons, who ended up in Egypt, God began to deal with the Israelites as His chosen, set-apart nation, bringing them out miraculously under Moses.