Why did one person of the triune God need to become the Redeemer?

Les explains that in eternity past, God the Father, God the Son, and God the Holy Spirit came together and by a determinate agreeing of their three minds decided to create the universe and put the human race on planet earth. They knew in foreknowledge that the human race would fall in the man Adam, and they knew in that predeterminate counsel that one person of that triune God would have to be a Redeemer. According to that predeterminate counsel of Acts chapter 2, the whole thing was brought moving. Les then notes that as a small part of that big picture, we come, and by the same triune counsel God put His finger on every one of us and said, 'I have a place waiting for you.' He also addresses the argument about whether we are elected or chosen before we had anything to do about it, and the opposite party claiming it was all free will. Les affirms that whosoever will sits over here.