The flesh is dead in its trespasses. Anything it does is the act of a decaying corpse. Nothing it does can put to death that which Christ has quickened.
The flesh is never dead, the lusts of it always live whilst we are in it, although it brings death to us, and we are tempted by the lusts of it always. But through Christ we are put to death to the flesh. Meaning that through Christ, God casts away those lusts so that they don't have a hold on us anymore.
Nothing Satan does in this flesh can put to death what God has quickened as long as we have faith and obey God, because he who is in us, is stronger than him who is in the world. But if we turn and start living by the will of the flesh again once we have been enlightened of God, because we love our own lives before God, then we are not only rejecting the holy spirit, but we are crucifying Christ again and put him to an open shame
Hebrews 6
For.it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost, And have tasted the good word of God, and the powers of the world to come, If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame
The current flesh shall never see the kingdom of Heaven. It will, as it already is, waste away.
The current flesh as we live to it, will never see the kingdom of God, but we will see the kingdom of God if we are dead to the will of it.
Otherwise why would we ask for God's kingdom to come every day so that God's will can be done? Gods will can't be done if we live by the will of the flesh, but if we are dead to its will and alive in God, then we will be living by God's will and his kingdom will be within us every day. If we have the holy spirit within, then we have the kingdom of God within. Because he belongs to Gods kingdom.
When speaking of the flesh, it's not the natural skin that we are in, but the lusts of our fleshly nature, and we have to be dying to those lusts every day to inherit the kingdom of God. For whilst we live in this flesh, we also have the fleshly nature that Satan has control of unless we are quickened by the spirit and we are truly born again of God, and once we are truly born of God, then we should be living by his will and not by the lusts of the flesh.
As one not in the flesh, but in the Spirit, sin has no dominion over me; I am no longer its slave. I am free from its power and its sting. I am a slave of righteousness. I am the very righteousness of God in Christ.
Sin only has no dominion over you if you obey God and not the flesh. And if you are truly a slave to righteousness, then that means you are always turning from sin and if you are the very righteousness of God in Christ, then that means you must never sin?
I'm not righteous at all, it's only Christ in me that is righteous and being in him through faith, he is teaching me through the spirit to live right before God, he's helping overcome my sins and by his righteousness I'm overcoming the flesh day by day and I'm alive in the spirit. And I'll remain being saved so long as I don't live by the lusts of the flesh again and turn from God and deny his will putting myself before him.
2 Corinthians 6
Be ye not unequally yoked together with unbelievers: for what fellowship hath righteousness with unrighteousness? and what communion hath light with darkness? And what concord hath Christ with Belial? or what part hath he that believeth with an infidel?
And what agreement hath the temple of God with idols? for ye are the temple of the living God; as God hath said, I will dwell in them, and walk in them; and I will be their God, and they shall be my people.
Wherefore come out from among them, and be ye separate, saith the Lord, and touch not the unclean thing; and I will receive you,
And will be a Father unto you, and ye shall be my sons and daughters, saith the Lord Almighty.
