As we have already mentioned, one of Fatima Zahra's (A.S.) names was "At Taherah" (the virtuous or pure). This meaning is related to the verse:
"And Allah only wished to remove all abomination from you, ye member of the Family and to make you pure and spotless." XXXIII:33
The above mentioned is of great importance because of its subtle meaning and significance.
This verse is considered the main source of virtues granted to Ahlul-Bayt (A.S.); around it various debates and many writings took place. It might be more appropriate to say that this verse was the field of debates, contradicting viewpoints and inconsistent opinions. This is especially true when it comes to who was meant by "the Family," or Ahlul-Bayt.
It is necessary to further elaborate on this subject, since the verse of purification declares, beyond doubt, that Fatima is pure.
Nevertheless, it may be beneficial to explain the meaning of the word "Rijs" or abomination mentioned in the verse.
"Rijs" means that Allah purified her from the monthly menstruation in addition to all abomination and depravities. "Rijs" is all that is deemed impure by human nature, conforms with evil doings, deserves punishment, detracts from one's good reputation, brings about sins, rejected by nature or mars any of the knightly virtues.
flower of ahlul bayt
Ibn Al-Arabi also said in AI-Futouhat Al-Makkiah, Chapter 29, which Rijs is "anything which detracts from one's character"
The definition that Al-Arabi gave for the word Rijs, is the definition for the word "infallible" which the Shiites believe is an inseparable character of all prophets, Imams, and Lady Fatima Zahra (AS).
It is indeed an excellent virtue and a great honor that Allah has bestowed upon some of his servants.
It is worthy to mention that infallibility is an inseparable trait of those who propagate divine laws; yet, because infallibility is a prerequisite for prophets and Imams in their roles of propagating divine rules, it does not mean that others, who also propagate, are safeguarded from sins.
Imam Ali (AS.) proved Fatima's infallibility using the verse of purification in his argument with Abu Bakr.
The Imam (AS) said:
"Abu Bakr do you read Allah's book?"
He answered: yes."
Imam Ali then said: "Then tell me about whom was the following verse revealed?:
‘And Allah only wishes to remove all abomination from you, ye Members of the Family, and make you pure and spotless.'
Was it not revealed in regard to us, Ahlul-Bayt?"
Abu Bakr said: "Yes, it was revealed regarding you."
He (AS) said: "If some men testify that Fatima, the Messenger's daughter, committed an abomination what would you do?"
He answered: "I would administer the legal punishment to her, just like any other Muslim woman!'
He (AS) then said: "If you did so, you would be an infidel in the eyes of Allah."
Abu Bakr said: "Why?"
Imam replied: "Because you would have rejected Allah ‘s testimony of her purity and virtue (infallibility), and surpassed people's testimony over it.
A manifestation of this purity, is safeguarding the person from impurity upon death, regardless of the fact that any human being-no matter how pious and obedient to Allah he is-becomes intensely impure upon passing away, making it obligatory to perform ablution (Ghusl) when touching his body. The dead person, himself, only becomes pure after being washed by others. Contrarily, the infallible are purified before and after death.
source : www.tebyan.net