Well, interesting, it looks like you are conversant in the Book of Mormon. If you notice, according to those verses, once we enter the eternal world, then for the wicked there is no turning back.
Is this at exactly at the time of death?
In my opinion, it is the day of Final Judgement when we are resurrected back into our physical bodies. Until the day of Final Judgement, we have a probationary period in which Jesus Christ offers himself as the sole mediator of ALL worlds, ALL people, and ALL of Heaven to as the Book of Mormon says:
Helaman 3:27 Thus we may see that the Lord is merciful unto all who will, in the sincerity of their hearts, call upon his holy name.
28 Yea, thus we see that the gate of heaven is open unto ball, even to those who will believe on the name of Jesus Christ, who is the Son of God.
29 Yea, we see that whosoever will may lay hold upon the word of God, which is quick and powerful, which shall cdivide sunder all the cunning and the snares and the wiles of the devil, and lead the man of Christ in a strait and narrow course across that everlasting gulf of misery which is prepared to engulf the wicked—
30 And land their souls, yea, their immortal souls, at the right hand of God in the kingdom of heaven, to sit down with Abraham, and Isaac, and with Jacob, and with all our holy fathers, to go no more out.
Notice, the above verses says a few things. Christ’s Atonement overcomes an everlasting gulf. Therefore the sacfrice of Jesus has everlasting properties. It bridges the gulf between God and Man. It puts one in the presence of God. It also places the righteous at the right hand of God which many scriptures allude to as a place of honor, and as place to govern under God (see Revelations as an example) as a Joint heir with Christ. And finally, this verse relates to man’s soul as immortal, in a fashion it is immortal like God’s. Is it of God’s quality? No not even close, but it is through Jesus that it does achieve that So then, what is the place of man in God’s universe? Well, it is for the righteous to be placed within his bossom and to have a place in his kingdom at his right hand.
My questions are from a sincere belief to understand.
Is this at exactly at the time of death?
Seems pretty clear from the text:
For behold, if ye have procrastinated the day of your repentance even until death, behold, ye have become subjected to the spirit of the devil, and he doth seal you his; therefore, the Spirit of the Lord hath withdrawn from you, and hath no place in you, and the devil hath all power over you; and this is the final state of the wicked
we have a probationary period
Can you point to the scripture that supports this?
Therefore the sacfrice of Jesus has everlasting properties
On a going forward basis. Still don't see the "backward" nature. Seems to say exactly the opposite.