With Adam, we fall from the Terrestrial world to the Telestial world. In the Telestial world we are under the law with no grace. The Telestial world is ruled by the Holy Ghost. As long as we do not deny the Holy Ghost, we can remain in the Telestial world. We are judged by our works. To be saved from the fall and return to the Terrestrial world, we need the atonement. The atonement of Christ promises salvation from the fall. Not Exaltation or anything else. So, those who gain a testimony of Christ are saved from the fall and raised back to the Terrestrial world. They started the path that leads to eternal life. They are covered by grace and not judged by their works. They had entered in at the gate and STARTED the path that leads to eternal life. They qualify to live during the Millennium with Christ who governs over the Terrestrial kingdom. (Consequently, there will be many from other religions who qualify to live in the Terrestrial world and Millennium because they have accepted Christ and his atonement and started the path that leads to eternal life.) The path to eternal life may be long or short, but it has an end. That end IS Eternal life which is sealed by the Holy Spirit of Promise. Everyone remains on the path to eternal life UNTIL the are sealed by the Holy Spirit of promise which seals eternal life. This is “the end”. The end of the path that leads to eternal life. The End of the probation. So when the scriptures say to “endure to the end” they mean endure to the end of the path that leads to eternal life, endure to the end of your probation. That end can come during this life or after this life. If you do not endure to the end of the path, then you have not gained eternal life and you are still on the path that leads to eternal life.