Isaiah 1:18-20 God speaks to his people, asking them to turn around from their sinful ways and become obedient to his laws, saying that 'though your sins be as 'scarlet' they can be made white as snow.
Another Answer:
The Bible doesn't say that "scarlet represents sin." Biblical symbols signal what they represent by their usage.
The color scarlet is used in the description of the coming end time Beast power and the "woman" who "sits upon it"... straddling it, holding the reins, guiding it... controlling it.
A "woman" in one prophetic Bible symbolism represents "God's church.
"Husbands, love your wives, even as Christ also loved the church, and gave Himself for it... for this cause shall a man leave his father and mother, and shall be joined to his wife... this is a great mystery: but I speak concerning Christ and the church..." (Eph.5:25-32).
Prophetically speaking, therefore... a "whore" represents a "false church."
"...I will shew unto thee the Judgment of the great whore that sitteth upon many waters... I saw a woman sit upon a scarlet coloured Beast... and the woman was arrayed in purple and scarlet colour..." (Rev.17:1-4).
These two scarlet-colored end time political and religious forces that shall jointly rule the world during the Great Tribulation are wicked and will wield the power of Satan:
"...the Dragon gave him (the Beast) his power, and his seat, and great authority..." (Rev.13:2).
They are wicked and evil and their symbolic color is "representative of sin." The Bible just doesn't "say" it outright.
In the Bible, scarlet is often used to symbolize sin and wrongdoing. It is also associated with royalty and wealth, as seen in references to Jesus being dressed in scarlet robes before his crucifixion. Additionally, scarlet is mentioned in the context of purification rituals and sacrifices in the Old Testament.
In the Bible, yeast represents sin.
rebellion
that sin and blasphemy are bad and and blasphemy is the only unforgivable sin
Nowhere in the Bible does it say that.
no
The Bible says very clearly that rebellion is like witchcraft. It says that like witchcraft is a sin, so is rebellion a sin.
James 4:17 - Therefore, to him who knows to do good and does not do it, to him it is sin. [NKJV]
In Chapter 2 of "The Scarlet Letter," Hester's sin is revealed to be adultery, as she has had a child out of wedlock. She is publicly shamed and required to wear a scarlet letter "A" on her chest to signify her sin.
None! The bible states "thou your sins be like scarlet (red), He will wash them white like snow. Red is the color represented as sin.
The scaffold, the scarlet letter itself, and Pearl are all devices in "The Scarlet Letter" that symbolize sin and its consequences. The scaffold is where public shaming occurs, the scarlet letter is a physical reminder of Hester's sin, and Pearl embodies the product of Hester's sin.
My apologies if I am mistaken, but I do not believe that phrase appears anywhere in the Bible.