Good points, Pamela and Mike. Here's more Scripture to consider.
Eph 2:11 So then, remember that at one time you were Gentiles in the flesh--called "the uncircumcised" by those called "the circumcised," done by hand in the flesh.
Eph 2:12 At that time you were without the Messiah, excluded from the citizenship of Israel, and foreigners to the covenants of the promise, with no hope and without God in the world.
Eph 2:13 But now in Christ Jesus, you who were far away have been brought near by the blood of the Messiah.
Eph 2:14 For He is our peace, who made both groups one and tore down the dividing wall of hostility. In His flesh,
Eph 2:15 He did away with the law of the commandments in regulations, so that He might create in Himself one new man from the two, resulting in peace.
Eph 2:16 He did this so that He might reconcile both to God in one body through the cross and put the hostility to death by it.
Eph 2:17 When Christ came, He proclaimed [Greek: preached] the good news of peace to you who were far away and peace to those who were near.
Eph 2:18 For through Him we both have access by one Spirit to the Father.
That phrase spirits in prison from 1Peter 3:19 is very off-putting, isn't it. At least it was for me. I spent days just re-reading it from many translations, checking definitions, and searching all over the place in the bible for answers. So, I ignored that phrase for a while and started paying attention to the verses around it and decided that the passages I have listed made the most sense spiritually. Of course, I could be totally off, but what I did find concerning Eph 2:11-18 was new to me and was as equally fascinating as 1Peter 3:19, not to mention edifying.
Gal 3:20 Now a mediator is not for just one person, but God is one.
Gal 3:21 Is the law therefore contrary to God's promises? Absolutely not! For if a law had been given that was able to give life, then righteousness would certainly be by the law.
Gal 3:22 But the Scripture has imprisoned everything under sin's power, so that the promise by faith in Jesus Christ might be given to those who believe.
Gal 3:23 Before this faith came, we were confined under the law, imprisoned until the coming faith was revealed.
The dividing wall of the law, this administration of death, is like a prison, like the prison that is sin and death. It keeps us separated from God through sin and through a deep-seated hatred for God, so it had to be dealt with. In dealing with it, Jesus, the mediator, could unite or reconcile the whole world to God.
1Ti 2:3 This is good, and it pleases God our Savior,
1Ti 2:4 who wants everyone to be saved and to come to the knowledge of the truth.
1Ti 2:5 For there is one God and one mediator between God and man, a man, Christ Jesus,
1Ti 2:6 who gave Himself--a ransom for all, a testimony at the proper time.
Looking at the definition of the word spirits from 1Peter 3:19, it seems clear to me, it's referring to those made of flesh and blood, but having the mind of Christ.
πνεῦμα
pneuma
pnyoo'-mah
From G4154; a current of air, that is, breath (blast) or a breeze; by analogy or figuratively a spirit, that is, (human) the rational soul, (by implication) vital principle, mental disposition, etc., or (superhuman) an angel, daemon, or (divine) God, Christ’s spirit, the Holy spirit: - ghost, life, spirit (-ual, -ually), mind. Compare G5590.
We can know they were in fact flesh and blood because of the verse after 1Peter 3:19.
1Pe 3:19 In that state (Christ's risen state) He also went and made a proclamation [Greek: preached] to the spirits in prison
1Pe 3:20 who in the past were disobedient, when God patiently waited in the days of Noah while an ark was being prepared; in it, a few--that is, eight people--were saved through water.
The spirits in prison were disobedient in the past, just as we were before Christ revealed Himself to us after His resurrection. If the ark represents Christ, what do we suppose Christ was being prepared for? Obviously, to baptize us into His death to pull down and destroy the deep-seated spiritual enmity between us and God, thereby giving us access to God; effectively revealing the Father to us after raising us back to a newness of spiritual life with a clean and clear conscience to God. That's why it's so important to believe our sins really have been forgiven.
1Pe 3:22 Now that He has gone into heaven, He is at God's right hand, with angels, authorities, and powers subjected to Him.
2Co 10:3 For although we are walking in the flesh, we do not wage war in a fleshly way,
2Co 10:4 since the weapons of our warfare are not fleshly, but are powerful through God for the demolition of strongholds. We demolish arguments
2Co 10:5 and every high-minded thing that is raised up against the knowledge of God, taking every thought captive to the obedience of Christ.
The law was limited because it was a fleshy and temporary means of waging war against sin. The physical Law could never have completely removed sin and death, thereby imprisoning us in a cycle of sin and death.
Rom 8:1 Therefore, no condemnation now exists for those in Christ Jesus,
Rom 8:2 because the Spirit's law of life in Christ Jesus has set you free from the law of sin and of death.
Rom 8:3 What the law could not do since it was limited by the flesh, God did. He condemned sin in the flesh by sending His own Son in flesh like ours under sin's domain, and as a sin offering,
Rom 8:4 in order that the law's requirement would be accomplished in us who do not walk according to the flesh but according to the Spirit.
The Law demanded an offering for the forgiveness of sins; ensuring the cycle of offerings for sin. However, when Christ came, He fulfilled all the Law once and for all, so our sins could be permanently forgiven by offering Himself for and because of our sins.
Php 2:7 Instead He emptied Himself by assuming the form of a slave, taking on the likeness of men. And when He had come as a man in His external form,
php 2:8 He humbled Himself by becoming obedient to the point of death--even to death on a cross.
Php 2:9 For this reason God also highly exalted Him and gave Him the name that is above every name,
Php 2:10 so that at the name of Jesus every knee should bow--of those who are in heaven and on earth and under the earth--
Php 2:11 and every tongue should confess that Jesus Christ is Lord, to the glory of God the Father.
Jesus didn't have to die, and no one took His life from Him. He offered Himself out of love and to bring us closer to Him and His Father by removing the enmity that imprisons us in sin and death. He also did it to show us how to be obedient to God in the Spirit. His outward works were a reflection of His inward Spirit.
While Ray may not have covered 1Peter 3:19 specifically, Ray did cover the same principles as described in 1Peter 3:19. I don't have the principles above completely nailed down, so it may be I haven't a clue as to what 1Peter 3:19 means. These are just other things to consider and things I remember from Ray and my studies. Take it all with a grain of salt.