for this very thing the gospel was preached to the dead so that men judged according to fleshly men live now according to God, spiritual (1 Peter 4:6)
... who will give an answer, words having ready, judging the living and the dead (1 Peter 4:5)
This is the very purpose the gospel was preached so that we existing dead should be made alive to God. So the spiritual and the fleshly are judged accordingly. Through a new birth spiritually we enter the kingdom of God.* So the best answer to whether I know God, or not, is that I have testimony from God (not of men, not of works like serving, giving, or that I raised my hand, said a prayer, went down the isle, have a certificate of baptism...) but have testimony from God and there are three that testify; spirit, blood, and water. God judges according to whether one is living, spiritual, or dead, fleshly.
... the one suffering fleshly has caused to cease, sin, so that no longer living your remaining days in fleshly human desires rather the will of God (1 Peter 4:1-2)
The purpose of suffering is to cause sin to cease in the body. Though we exist spiritual we walk this earth in a fleshly body. The purpose of suffering fleshly is to make useless the opposing force of the flesh, in it desires and passions that are against the will of God. The one who has been renewed in the spirit of their mind, having the "mind of Christ" can discern and accept God's will as good and pleasing. The old fleshly man which was defined in its fleshly desires was crucified with Christ, "know this, because the old man was crucified so that the body of sin is accordingly inactive so we no longer serve sin, for the one who has died has been set free from sin" (Romans 6:4-9). Sin is rendered useless or inactive or caused to cease through suffering being united in his death and suffering.
for the time is purposed sufficient that the nations purpose to work out their passage in sensuality, passions... (1 Peter 4:3)
Our passage from here to eternity was chosen by God before he created the world. God creating the world, giving man a chose, was intentionally purposed. It was purposed in this time for sin to grow into fullness, so that when it is fully grown it gives birth to death (James 1:15). The judgement of sin is according to the fleshly desires and passions. The law of sin and death, as Paul calls it, is being worked out in the flesh. We who are spiritual escape this law of sin and death through new birth of the Spirit receiving a new law.
for the law of the Spirit of life in Christ Jesus set you free from the law of sin and death, for what the Law [Mosaic] was powerless and weak [useless] through the flesh, God sending his own [Son] in the same likeness of sinful flesh and as sin judged accordingly sin in the flesh... (Romans 8:1-5)
It is a profound mystery set forth and purposed through the gospel. To do away with sin by making us spiritual and capable of fulfilling God's spiritual laws. The Mosaic Law was weak and useless because of the flesh which has no capability or power to submit the the spiritual laws of God and his righteous requirements, set forth under the law (Romans 8:7). What was weak and useless, can not mature and bring one into the fullness of God, so to render sin useless in the flesh.* But this is what God purposed in the gospel from when he created the world.
... so that the righteous requirement of the law [is] fulfilled in us, the ones not walking according to the flesh rather according to the Spirit... (Romans 8:4-8)
A mystery God hid in the beginning and has purposed now in Christ working it out through the church. Just as the flesh is working out sin unto fullness the result being death, God's Spirit in the believer is working out righteousness, the result of the fullness of God is life and peace (Romans 8:10; Galatians 5:17-25). This is done not under the Law but through growth in knowledge of Jesus as we are being conformed to the image of Christ. Thus having the mind of Christ we walk according to the new spiritual man not the old fleshly man, and can fulfill the righteous requirement of the law. So the law is fulfilled in us, the ones not walking according to the flesh but the Spirit, as the Spirit renders useless the flesh and its desires.
for those led of God's Spirit these exist the sons of God, for not receiving a spirit of slavery leading back to fear rather receiving a Spirit of adoption in whom we cry out Abba Father, the Spirit himself together testifying of our spirit because we exist children of God... (Romans 8:14-17)
If the Spirit of the one raising Jesus from the dead dwells in us, the one raising Christ will make alive our mortal body through the Spirit. If we are united in his death also we will be united in his life (Romans 6:1-4). So the the old man is crucified with Christ, being united in his death so that sin is rendered useless, a dead man no longer sins (Romans 6: 5-7). To be conformed to Christ is to be conformed to his death so as to be also be conformed to his life. This is growth from a child who has testimony of adoption to a son who has overcome.
... and if children also heirs, heirs of God, now together heirs with Christ provided we together suffer so that also glorified with him (Romans 8:17)
We are heirs provided we suffer with him. One must suffer to overcome the flesh. "Therefore as Christ suffered fleshly, arm yourselves also with the same way of thinking, because the one suffering fleshy is finished with sin..." (1 Peter 4:1-2). This is the purpose of suffering, why we suffer fleshly on this earth, "so that also glorified with him." The blessings in Christ are spiritual (Ephesians 1). The same Spirit that raised Jesus and dwells in us brings life to this mortal body by rendering sin useless (Romans 8:11).
that I know him and the power of his resurrection and the fellowship of his sufferings together conforming to his death, if in a certain way to arrive at the resurrection from the dead (Philippians 3:10-11)
There will be a resurrection from the dead in terms of eternity. However, Paul also refers to life being brought to this mortal body. The Spirit of life is through righteousness, therefore "the certain way" we arrive at the resurrection, life in this mortal body, is to be conformed to his death. And if we are conformed and united in his death, we have rendered useless sin, therefore bear fruit of righteousness which fruit is life and peace. God purposed in Christ both to do away with the penalty of sin through a sacrifice acceptable to him and to render useless the power of sin (1 John 3:5)
For the Lord disciplines the ones he loves, chastising all whom he receives as sons, so endure your trials to the extent of discipline, God is treating you as a son... (Hebrews 12:6-7)
When the suffering comes through various trials I am to arm myself with the same thinking as Christ. Jesus did nothing wrong, but they persecuted him to the point of death. He was God who dwelt among men, full of wisdom and righteousness and life, a light to the world. He came among his own but most rejected him (John 1:10-13). Jesus cried over Jerusalem because he knew they would reject him. When they thought of him as nothing, esteemed him not of godly majesty and honor deserving him, despising and rejecting him, he did not judge but entrusted himself to the who judges justly, "he himself bore our sins in his body on the tree so that living, dying to sin, living to righteousness, of his wounds we are healed' (1 Peter 2:23-24). By dying to the fleshly desires, of his suffering we have fellowship, participating in his wounds we are healed.
Although existing a Son, he learned obedience from what he suffered (Hebrews 5:8)
Jesus the Son of Man learned to listen and heed God through suffering, just as we are to. We are to arm ourselves with the same mindset in suffering as there is a purpose just as Jesus suffered purposedly. The word obedience (ὑπακοή, hypakoúō (from hypó, "under" and akoúō, "hear") speaks of listening and heeding. Being able to hear or discern and to be in compliance with that which is heard is to have a mind that approves of God's will as pleasing, perfect, and good. It begins with a new birth of the Spirit as the fleshly man can not submit to the spiritual things of God. Then in suffering we do away with sin, being conformed to his death, united in his death, having fellowship in his suffering so that the body of sin is rendered useless so to also partake of his life. We suffer so as to be conformed to the image and glory of God in Christ Jesus.