Q. In Matthew 21 :43 it seems that the kingdom will be taken from those outlined in v45. Do you think this refers to all Israel? Further, who are the people to whom it will be given, and when will this happen?
A. Matt. 21:33-46 is the Parable of the Tenants. In the parable Jesus summarized Israel’s treatment of the prophets and other servants God had sent to them. God’s covenant with Israel was a national covenant, meaning everyone in the nation was obligated to its terms. So when the leaders executed His son, God saw to it that the entire nation ceased to exist. Since then individual Jews can be reconciled to God through the Church, but the national covenant has yet to be reinstated.
The people to whom the kingdom would be given is the group we know as the Church. God shifted His emphasis to us shortly after the Resurrection, and it has been that way ever since. After God has taken the Church to our eternal destiny, He will return and reestablish His covenant with Israel (Acts 15:13-18). After the end times judgments have been concluded He will restore the Kingdom to Israel during what we know as the Millennium .
You can read my study on the Parable Of The Tenants here.