The categories of Shirk are three:
- Shirk Akbar (major Shirk)
- Shirk Asghar (minor Shirk)
- and Shirk Khafee (hidden Shirk)
As for Shirk Akbar: It requires the futility of the deeds (of an individual) and the eternal existence in the Fire for the one who died upon it. As the Most High said:
"But if they had joined in worship others with Allaah, all that they used to do would have been of no benefit to them." - Al-An'aam (6):88
And the Most High said:
"It is not for the Mushrikoon (polytheists, idolaters, pagans, disbelievers in the Oneness of Allaah), to maintain the masaajid of Allaah (i.e. to pray and worship Allaah therein, to look after their cleanliness and their building, etc.), while they witness against their ownselves of disbelief. The works of such are in vain and in Fire shall they abide." - At-Tawbah (9):17
And whoever died upon that, Allaah will not forgive him, and Paradise is forbidden for him. As Allaah (subhana wa ta'aala) said:
"Verily, Allaah forgives not that partners should be set up with him in worship, but He forgives except that (anything else) to whom He pleases" - An-Nisa (4):48
And the Most High said:
"Verily, whosoever sets up partners in worship with Allaah, then Allaah has forbidden Paradise for him, and the Fire will be his abode. And for the Dhaalimoon (polytheists and wrong-doers) there are no helpers." - Al-Ma`idah (5):72
And from the types of Shirk Akbar are: calling upon the dead and the idols, seeking rescue from them, swearing by them, offering animal sacrifices to them, and similar to that.
And as for Shirk Asghar: then it is what has been established from the texts of the Book or of the Sunnah, as being designated as Shirk, but it is not from the types of Shirk Akbar. Such as riyaa` (performing a deed only to be seen by others) in (the performance of) some deeds, swearing by other than Allaah, saying: What Allaah willed (Maa shaa` Allaah), and so and so willed, and similar to that.
Due to the statement of the Prophet (salallaahu 'alaihi wa sallam): What I fear for you the most is the minor shirk So he was asked concerning it, so he said: 'ar-Riyaa'". Reported by al-Imaam Ahmad, at-Tabaraani, and al-Bayhaqee from Mahmood ibn Lubayd al-Ansaari (radiallaahu 'anhu) with an authentic chain. And it was reported by at-Tabaarani with authentic chains from Mahmood ibn Lubayd, from Raafiya` bin Khadeej, from the Prophet (salallaahu 'alaihi wa sallam).
And his (salallaahu 'alaihi wa sallam) saying: Whoever swears by other than Allaah, then he has indeed committed Shirk. Reported by al-Imaam Ahmad with a saheeh chain from 'Umar ibn al-Khattaab (radiallaahu 'anhu) and reported by Abu Dawood and at-Tirmidhee with a saheeh chain from the hadeeth of Ibn 'Umar (radiallaahu 'anhu) from the Prophet (salallaahu 'alaihi wa sallam).
He (salallaahu 'alaihi wa sallam) said: "Do not say: 'What Allaah willed, and so and so willed', rather say: 'What Allaah willed, then so and so willed.'" Reported by Abu Dawood with a saheeh chain from Hudhayfah bin al-Yamaan (radiallaahu 'anhu).And this type (of Shirk) does not dictate apostasy, nor does it necessitate eternal existence in the Fire but it makes deficient the perfection of Tawheed, which is an obligation.
As for the third type: and it is as-Shirk al-Khafee and the proof of this is the statement of the Prophet (salallaahu 'alaihi wa sallam): "Shall I not inform you of what I fear for you more than the Maseeh ud-Dajjaal (the false messiah)?" They (the companions) said: 'Of course, O Messenger of Allaah!' He (salallaahu 'alaihi wa sallam) said: "It is the hidden Shirk (Khafee). A man stands for prayer and beautifies his prayer for those who are watching him." Reported by al-Imaam Ahmed in his Musnad from Abu Sa'eed al-Khudree (radiallaahu 'anhu).
And it is more befitting that Shirk be divided in to two types: Akbar (major) and Asghar (minor). As for the hidden Shirk, then it is contained in them both.So it is found in the major (Shirk), like the Shirk of the Munafiqoon (hypocrites). Because they hide their false aqa'id (creeds), and show Islaam outwardly with duplicity and fear for their ownselves.
And it is in the minor Shirk, such as riyaa`, as is related in the hadeeth of Mahmood ibn Lubayd al-Ansaari that was presented and the hadeeth of Abu Sa'eed that was mentioned. And Allaah is the One with Whom is success.
Source: Duroosul Muhimmah Li 'Aamatil Ummah, Lesson 4
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Subhanak Allaahuma wa bihamdika ash-hadu anlaa illaaha illa anta astaghfiruka wa atubu ilayk
If I said anything correct, then it is from Allaah (subhanahu wa taa'ala), and if I erred, then that is from me and shaytan.