Prove it from the scriptures. I say all you can do is quote scriptures which once thoroughly inspected prove to say something else.
Bet you cannot prove it.
Sorry for the long post, but we ARE born with a sin nature. And yes, I can prove it. IT's all in the bible.
All men are mortal, dying creatures because they inherit from Adam a nature that is mortal and also prone to sin. This is not a crime and for it men are not guilty. In time, however, all men do sin and become guilty before God. Because all men are descendents of Adam, he is therefore a "federal head".
Romans 5v12 "Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned:"
1 Cor 15v21-22 "For since by man came death, by man came also the resurrection of the dead.
22 For as in Adam all die, even so in Christ shall all be made alive."
Jesus had the same nature that he got from his mother. He was like us. Hebrews 2v14 "Forasmuch then as the children are partakers of flesh and blood, he also himself likewise took part of the same; that through death he might destroy him that had the power of death, that is, the devil;"
Romans 8v3 "For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh:"
Jesus did not sin, because God was working through His son. (Acts 2). Sonship did not make him sinless, but made sinlessness possible. "Then answered Jesus and said unto them, Verily, verily, I say unto you, The Son can do nothing of himself, but what he seeth the Father do: for what things soever he doeth, these also doeth the Son likewise. For the Father loveth the Son, and showeth him all things that himself doeth: and he will show him greater works than these, that ye may marvel."
The mistake that you made on your post was that it is often made in reference to the principle of sin in the flesh is that guilt must be assigned wherever there is sin. That is a huge mistake. There are two categories of sin. Sin itself is simply the absence of righteousness (1 John 5:17). The two categories of sin are the transgressions of divine law (which does assign personal guilt) and sin nature (which assigns no guilt whatsoever). This is because of the divine judgment of death in Eden for that first sin. That was a judgment of death nature, not immediate execution. Mankind was degraded from a non-dying (but obviously not immortal) nature into a guaranteed dying nature (mortality). At that time the serpent philosophy that they chose over God's right-ness, became an active force in them... which is why temptations issue from within us. We don't need a serpent to tempt us anymore, because of our serpent nature. This is why Jesus was depicted as the bronze serpent that saved the Israelites from a horrible death from the venom of the sand viper in the wilderness (Num 21:9; John 3:14-15).
The signature doctrine of the antichrist system was prophesied to be the denial of the "flesh" of Christ (1 John 4:3, 2 Jn vs 7). That "flesh" of Christ is massively significant. This is why the memorial bread (broken before ingesting) represents that "flesh" of Christ and the temple veil torn from heaven to earth exactly at the point of the death of Jesus represents the "flesh" of Christ (Heb. 10:19-20). That "flesh" of Christ was where sin resided, prompting the temptations he endured but without failure (Heb. 4:15). Jesus was "made sin" at his birth. Because Jesus never allowed sin to "conceive" from the guilt free temptation stage into the guilt assignment of transgressional sin, he condemned that sin in his flesh through his voluntary death by crucifixion. This act declared God was "right" to demand death for sin. The death of Jesus declared the righteousness of his Father, just as the baptism of Jesus (projecting his death and resurrection) declared the righteousness of his Father (Matt 3:14-15).
So you see, we do have a sin nature. We are prone to sin. Jesus had the same nature as us, but did not sin. He "had to be like us" to conquer sin in the flesh.