Free will or God's will, or both.

God said about Jacob,"I love him, and Esau shall not inherit the promise, but I have chosen Jacob to inherit my promise".

Before Jacob was born, before he ever did anything, God sovereignly elects him. God does the calling. God has no obligation to call anyone, but He calls whom He decides, and whom He loves, and whom He desires to show mercy.

This is God's will, and it's going to happen.

What about Jacob's free will? I believe it's seen here: "Then Jacob was left alone; and a Man wrestled with him until the breaking of day. Now when He saw that He did not prevail against him, He touched the socket of his hip; and Jacob's hip was out of joint. And He said, "Let Me go for the day breaks."
But he said, "I will not let You go unless You bless me!"
So He said to him, "What is your name?"
He said, "Jacob." Gen. 32:24-27

Is Jacob a "spirtual-robot" here? Hardly. And yet God chose him before he was born. God's will is done, and Jacob isn't a "robot", but freely wrestles with God, and cries out, "Bless me!"

It doesn't get any more real than this! This was Jacob's free will crying out to God to bless him. And it doesn't get any more sovereign than this either. This was a sovereign God who chose Jacob before he was ever born. And this is a merciful God, whose grace was upon Jacob every moment of his life.

I truly believe Jacob is no different than anyone our sovereign Lord elects to inherit His promise of eternal life. And it's eternal life which is the ultimate gift for a sinner whom God choses. All other blessings, though they need to be received with joy and thanksgiving, are really insignificant when compared to the gift of eternal life, which is Jesus Christ Himself. Jesus is our eternal life. He was Jacob's eternal life as well.

"And this is eternal life, that they may know You [Father], the only true God, and Jesus Christ whom you have sent". John 17:3