Yes, it is instant, to the person dying. That's why I don't see what the problem is. (and God to God who is not even trapped in time, of course, would also see the person as "alive"). It is not any "interim place" such as a purgatory. That's the whole point. It's the traditional side that teaches an "interim place" of a disembodied existence, until the body is added back later. Has anyone ever though of why the body is resurrected, if the disembodied "heavenly existence" is the real deal?
In Genesis 35, we read this about the soul departing from Rachel when she died, making soul sleep an impossibility: 18 And it came to pass, as her soul was in departing, (for she died) that she called his name Benomi: but his father called him Benjamin. 19 And Rachel died, and was buried in the way to Ephrath, which is Bethlehem (parenthesis in the original).
As she was dying, she named him. She didn't name him
after her soul departed. How would anyone even hear that?
And if the issue is the word "Departing", that is metaphorical language. Just like people try to say "sleep" is metaphorical language, this is a matter of weighing all the passages, and interpreting the less clear ones in light of the more clear ones. Often, the opposite is done, as in the following:
One of the most important scriptures refuting soul sleep is found in Ephesians and it concerns Christ and His resurrection:
Ephesians 4:7-10 But unto every one of us is given grace according to the measure of the gift of Christ. Wherefore he saith, when he ascended up on high, he led captivity captive, (Now that he ascended, what is it but he also descended first into the lower parts of the earth? He that descended is the same also that ascended up far above all heavens, that he might fill all things).
Jesus lead captivity captive when He descended into the lower parts of the earth. In other words, He descended and then ascended from there taking with Him a host of captives (those who waited for His coming). That they were there waiting to be led out shows the non-existence of soul sleep:
LED CAPTIVITY 161. aichmalosia, aheekh-mal-o-see'-ah; from G164; captivity:-captivity.
LED CAPTIVITY 164. aichmalotos, aheekh-mal-o-tos'; from aichme (a spear) and a der. of the same as G259; prop. a prisoner of war, i.e. (gen.) a captive:- captive.
At death, the spirits of men of faith were held captive at death in Hades and released from there when Jesus descended there after His death (see I Peter 3:19 and I Peter 4:6). Jesus preached to the spirits held captive, whether they be the spirits of those in Noah's day or not. He didn't preach to a sleeping crowd.
--this is talking about His burial and resurrection, and the redemption from the curse of sin it brought us. It says not a thing about carrying souls up to heaven (or "Abraham's bosom"), or carrying a whole section of Hades itself up to Heaven.
1Pet.3:18-20 and 4:3-6 are also often used, and many in the past have combined this with Christ's burial, and have posited a whole scenario of Christ "descending into Hell", which must have had two sections, "paradise" for the righteous, and a place of suffering for the wicked; and that Christ preached to its inhabitants, and even bringing the righteous (such as Noah) back up with him, to Heaven. Some parts of this are now rejected by various interpreters, but still these passages do appear as "proofs" that the righteous dead before Christ were alive in Sheol/Hades, and now they are alive in "Heaven". Others see the reference to Noah as referring to fallen angels, who existed back then as well as now. But for one thing, fallen angels are not "
sometimes" disobedient, and the other angels are never disobedient. It is useless to "preach" to either. In the context, above we see Paul is discussing unsaved people
now (i.e. in his time, and of course it applies to our time as well), who taunt Christians for not living like them anymore. It was this same type of people in the "world" in Noah's time, who mocked as he built his ark to escape the coming judgment, and all soon perished. It was not those people in Noah's time who were being preached to by Christ, (unless you see Christ preaching to them
through Noah) but just a comparison of the wickedness. The point is, Christ's message is being offered to these people in the world today, enslaved in the prison of sin and condemnation. This passage even seems to be a reference to (fulfilment of) the messianic prophecy in Isaiah 42:1-7 "Behold My Servant, whom I uphold; My Elect, in whom My soul delights. I have put My Spirit on Him; He shall bring out
judgment to the Gentiles. He shall not fail nor be discouraged until He has set judgment in the earth; and the coasts shall wait for His law. So says God, the LORD He who created the heavens and stretched them out, spreading out the earth and its offspring; He who gives breath to the people on it and spirit to those who walk in it. I the LORD have called You in righteousness, and will hold Your hand, and will keep You, and give You for a covenant of the people, for
a Light to the Gentiles; to open the blind eyes,
to bring out the prisoners from the prison, those who sit in darkness out of the prison house".
This is even recognized in chain references. Sin is many times over referenced as both "prison" and "death".
Hanegraaf, in
Christianity in Crisis, p.396, uses this passage as a proof text of Christ descending to Hades to preach to the righteous in "paradise", but then his own
Christian Research Journal (12-97 p.24,25) Luke Wilson, answering Mormon doctrine of the salvation of the dead (a logical possibility with common interpretation of the passage) shatters the idea. The passage suggests this happened
after Christ was put to death,
and then made alive. And he ultimately shows from the Greek that this passage is describing Christ's PROCLAMATION of victory which "took place in the context of this journey". (though he takes the view that it was to fallen angels; though after the resurrection). In the notes he adds :"I do not believe 1 Pet.3:18 ff can properly be understood in connection with the doctrine of Christ's descent into Hades during the time His body lay in the tomb".