Because it doesn't comport with God's word (1 Corinthians 3:1-3; 11-15; 5, 6, 11; Hebrews 5:11-14; Galatians 3:1-3; 1 John 1:8-10; Romans 14:1, Revelations 2, 3, etc.) and because no one but God has any idea what perfect obedience actually is.
It comports to these words of God...“Be ye therefore perfect, even as you Father which is in heaven is perfect.” (Matt 5:48)
“I in them, and thou in me, that they may be made perfect in one; and that the world may know that thou hast sent me, and hast loved them, as thou hast loved me." (John 17:22-23)
“Knowing this, that our old man is crucified with him, that the body of sin might be destroyed, that henceforth we should not serve sin.
For he that is dead is freed from sin.” (Rom. 6:6-7)
"There is therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit." (Rom 8:1)
"Awake to righteousness, and sin not; for some have not the knowledge of God: I speak this to your shame." (1 Cor 15:34)
"For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him." (2 Cor 5:21)
"Finally, brethren, farewell. Be perfect, be of good comfort, be of one mind, live in peace; and the God of love and peace shall be with you." (2 Cor 13:11)
"Let us therefore, as many as be perfect, be thus minded: and if in anything ye be otherwise minded, God shall reveal even this unto you." (Phil 3:15)
"Unto the pure all things are pure: but unto them that are defiled and unbelieving is nothing pure; but even their mind and conscience is defiled.
They profess that they know God; but in works they deny him, being abominable, and disobedient, and unto every good work reprobate." (Titus 1:15-16)
"Forasmuch then as Christ hath suffered for us in the flesh, arm yourselves likewise with the same mind: for he that hath suffered in the flesh hath ceased from sin;" (1 Peter 4:1)
"According as his divine power hath given unto us all things that pertain unto life and godliness, through the knowledge of him that hath called us to glory and virtue:
Whereby are given unto us exceeding great and precious promises: that by these ye might be partakers of the divine nature, having escaped the corruption that is in the world through lust." (2 Peter 1:3-4)
“Wherefore the rather, brethren, give diligence to make your calling and election sure: for if ye do these things, ye shall never fall:" (2 Peter 1:10)
"Wherefore, beloved, seeing that ye look for such things, be diligent that ye may be found of him in peace, without spot, and blameless." (2 Peter 3:14)
“But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin.” (1 John 1:7)
Whosoever is born of God doth not commit sin; for his seed remaineth in him: and he cannot sin, because he is born of God.” (1 John 3:4-9)
“We know that whosoever is born of God sinneth not; but he that is begotten of God keepeth himself, and that wicked one toucheth him not.” (1 John 5:18)
Why do you think Paul, Peter, James and John wrote the prohibitions against sinful conduct that they did in their various letters? Because all of the Christian brethren were living perfectly sinless lives? Were that the case, none of the moral commands issuing from the writers of the NT would have been necessary! The enormous stream of commands given by the NT writers to do some things and not do others, then, was in response to the conduct and thinking of those to whom they were writing and so reveals the often very sinful and ignorant way in which Early Church believers were behaving.
He wrote the letters to both support the true converts and separate the posers from among the true.
Sinners are neither in Christ or "believing".
But, you see, the born-again person has already been made perfect in Christ, which is the only reason God accepts them as His own. In their spiritual position in Christ, the born-again believer is already redeemed, justified and sanctified (1 Corinthians 1:2, 30), and thus able to enter into God's eternal kingdom and family. As Paul wrote, the saved person is "accepted in the Beloved" (Ephesians 1:6) and there is no more to be done to make God's acceptance more complete or permanent. Christ has done it all, perfectly satisfying all of God's holy demands for justice and punishment of sin. To think, then, that, by dint of one's own efforts to live in a holy way, one secures one's salvation - in essence, completes one's salvation - is to think that one shares in the role of Savior, which is a deeply blasphemous idea. Christ only is Savior and he shares the glory for what he has done at Calvary with no one.
He has indeed been (re)made perfect.
And he can remain that way, thanks be to God !
In any case, you have no idea, really, what perfect obedience is.
But I do know what perfect obedience to God is.
Why don't you ?
You can only have a proper understanding of perfection if you are perfect, which you aren't.
By removing the ways, you can remove the possibility.
But as you have already admitted above that we are (re)made perfectly, your back-track smells to high heaven.
Perfection exists only in God and none of us have any idea of the fullness of what it is for God to be perfect. "Now we see in a mirror darkly, knowing only in part" Paul wrote (1 Corinthians 13:12); only on the other side of eternity will we have the sort of clarity we presently lack about many things, including what perfection actually is. In other words, you have no idea what you're aiming at if you're aiming to be perfectly obedient to God and can have no idea, then, whether or not you've reached perfection. For all you know, being unavoidably ignorant of what perfection truly is, you're nowhere close to it. What a horrible surprise you're going to have when you stand before God one day and realize just how far from perfection you've been. But you'll also be very, very thankful that God's acceptance of you doesn't have anything to do with you, with how close your obedience came to His own divine perfection.
I was water baptized into God after my true repentance from sin.
You are in essence admitting you have yet to repent of sin and get washed of your past sins by the blood of Christ at water baptism in the name of Jesus Christ for the remission of past sins.
The horribly imperfect will receive no mercy from God on the day of judgement.
Just a fair judgement.
If this were true, then no one could be saved. But God does hear at least one prayer of the sinner: The prayer of repentance from, and confession of sin, and trust in Christ as Savior and Lord (1 John 1:9; Romans 10:9-10; James 4:6-10).
Plenty are willing to serve Christ without reservation or any man's accommodations for ongoing sin.
Your POV is defeatist.
Anyway, there is no child of God who is not guilty of sin, no matter how long they've walked with God.
Tell that to Jesus.
Being sin-steeped creatures, believers don't recognize much of what God considers sin in their lives to be sin. But, over time, God illuminates the dark, sinful corners of a born-again person's life, bringing them ever more fully into the light of holiness. This is a life-long process, the believer growing holier and holier as they approach eternity; but never do they ever become perfectly sin-free. Paul the apostle acknowledged this very plainly:
You ignore the effects of rebirth.
The sin-steeped creatures have bene crucified and buried with Christ.
The new creature was raised with Christ to walk in newness of life.
Someone for got to tell you the new creature, born of God's seed, is as holy as Jesus' first Son is.
Philippians 3:12-14
12 Not that I have already obtained this or am already perfect, but I press on to make it my own, because Christ Jesus has made me his own.
13 Brothers, I do not consider that I have made it my own. But one thing I do: forgetting what lies behind and straining forward to what lies ahead,
14 I press on toward the goal for the prize of the upward call of God in Christ Jesus.
Though an apostle of the Early Church to the Gentiles and the second greatest contributor to the New Testament, Paul was not perfect (vs. 12) but continued to "press on" toward the "upward call" of God in Christ. If he did not claim perfection, what are you doing making such a claim for yourself - especially when your claim in no small part rests upon Paul's teaching!
I am glad he wrote of the perfection he had yet to attain in both verses eleven, (the resurrection of the dead), and verse twenty-one. (the glorified body).
If a sinner turns from sin, he sins no more.
If he sins again, his repentance from sin was a lie to God.
That is no the way to forge any kind of relationship with God.
Only separation.