From the main tasks of God’s Messengers was to emphasise purification of the self:
God has been truly gracious to the believers in sending them a Messenger from among their own, to recite His revelations to them, to make them grow in purity, and to teach them the Scripture and wisdom- before that they were clearly astray. [Aali-Imran 3:164]
Just as We have sent among you a Messenger of your own to recite Our revelations to you, purify you and teach you the Scripture, wisdom, and [other] things you did not know. [al-Baqarah 2:151]
God ordered Musa [peace be upon him]: ‘Go to Pharaoh, for he has exceeded all bounds, and ask him, “Do you want to purify yourself [of sin]? [an-Nazi’at 17-18]
Ibrahim [peace be upon him], after he finished building God’s House prays: Our Lord, make a messenger of their own rise up from among them, to recite Your revelations to them, teach them the Scripture and wisdom, and purify them: You are the Mighty, the Wise.’ [al-Baqarah 2:129]
It is He who raised a messenger, among the people who had no Scripture, to recite His revelations to them, to make them grow in purity (wayuzakkeehim) [i.e. spiritually] and teach them the Scripture and wisdom - before that they were clearly astray [al-Jumuah 60:2].
God made success or failure a result of purified souls or unpurified ones.
Prosperous are those who purify themselves [al-A’la 87:14]
The one who purifies his soul succeeds and the one who corrupts it fails. [ash-Shams 91:9-8]
God urges Man to strive in His cause and not for the cause of any other ideological agenda to attain guidance:
But We shall be sure to guide to Our ways those who strive hard for Our cause: God is with those who do good. [al-‘Ankaboot 29:69]
However, unfortunately many adherents of Islam, self-accredit to be upon the correct methodology or to the ‘saved sect’ by conceitedly ascribing to, for example Ahlu-Sunnah-wal-Jama’ah [whether Salafi, Deobandi, or Barelawi] Sunni, Shi’i, Ahlul-Hadith, Ibaadi, Sufi or Ahmedi and etc. they bear witness that they are upright and true Muslims according to their sectarian perception in exclusion to others who differ with their methodology - attributing purity for oneself or one’s exclusive group/sect/denomination. Thereby, indirectly ascribing [worthy of] salvation for oneself. This mindset contravenes with the Quran:
Those who avoid the major sins and immoralities, only [committing] slight ones. Indeed, your Lord is vast in forgiveness. He was most knowing of you when He produced you from the earth and when you were fetuses in the wombs of your mothers. So do not claim yourselves to be pure; He is most knowing of who is mindful of Him. [An-Najm 53:32]
Even the prophet had no knowledge of who was righteous/saved or wrongdoers/doomed unless God informed him:
And from among those who are round about you of the dwellers of the desert there are hypocrites, and from among the people of Medina (also); they are stubborn in hypocrisy; you do not know them; We know them; We will chastise them twice then shall they be turned back to a grievous chastisement. [Tawbah 9:101]
There is further emphasise in the following verse:
“Say: I am not the first of the messengers, and I do not know what will be done with me or with you: I do not follow anything but that which is revealed to me, and I am nothing but a plain warner” [al-Ahqaf 46:9]
Moreover, had God not given the Prophet [peace be upon him] succour even he would have inclined partially to the polytheists’ subterfuge:
[Prophet], the disbelievers tried to tempt you away from what We revealed to you, so that you would invent some other revelation and attribute it to Us and then they would have taken you as a friend. If We had not made you stand firm, you would almost have inclined a little towards them.[Al-Isra 17:73-74]
Even the saintly beings, Angles or Prophets seek to gain proximity to God:
Those they call on are themselves seeking the means by which they might approach their Lord — even those who are the closest to Him — and are hoping for His mercy and fearing his punishment. The punishment of your Lord is truly something to be feared. [al-Isra 17:57]
So how can anyone have the audacity to have such a conceited mindset that ascribes purity and thereby salvation to oneself by boldly claiming to be upon the ‘saved sect’ or upon the “Sunnah,” and etc. in exclusion to others.
[Prophet], have you considered those who claim purity for themselves? No! God purifies whoever He will: no one will be wronged by as much as the husk of a date stone. [An-Nisa 4:49]
(Part of verse an-Nur 24:21) If it were not for God’s bounty and mercy towards you, not one of you would ever have attained purity. God purifies whoever He will: God is all hearing, all seeing.
And Allah knows best
For Younger Readers
God teaches in the Quran, the holy book of Muslims that:
Everyone must try their best to better themselves as a person by following God’s guidance
Only God knows who is truly righteous and good
Beware of being self-righteous and smug
Avoid sectarian exclusive claims of salvation (being saved from Hell and going to Paradise)