Will Jesus ever cast out one of God's chosen people?
No. Jesus declared that all whom the Father gives Him will come to Him, and whoever comes He will in no wise cast out. Anyone God has chosen, elected, and sent to Christ will never be cast out. This statement means exactly what it says.
Les teaches from John 6:37 that Jesus is speaking, and that all the Father gives Him shall come to Him. God makes the first move; no unbeliever seeks God on his own because it is not in him. If someone has an appetite for the things of God, God put it there first. Jesus then says that the one who comes as a result of God's moving him, He will in no wise cast out. Les emphasizes that anybody God has chosen, elected, and sent to Him would in no wise ever be cast out, and that means what it says. He then directs attention to John 10:28.
All that the Father giveth me shall come to me; and him that cometh to me I will in no wise cast out.