Pre-Islamic Arabia: Jahili Arabs' Unique Idolatry/Polytheism
The interesting thing about the jahili Arabs was that they believed in the same God that we Muslims believe in, by the same name and attributes, and that is Allah. They never depicted Allah as an idol. They made idols of al-Lat (اللات), Hubal (هبل), al-Uzza (العزى), Manat (مناة), etc., but they never made an idol of Allah because they knew Allah could not be represented by an idol. They knew Allah was their Creator, Originator, and Sustainer. Allah says in the Quran:
وَلَئِن سَأَلْتَهُم مَّنْ خَلَقَهُمْ لَيَقُولُنَّ الله
"If you were to ask them who created them, they would say, 'Allah.'" [Quran, 43:87]
وَلَئِن سَأَلْتَهُم مَّنْ خَلَقَ السَّمَاوَاتِ وَالْأَرْضَ لَيَقُولُنَّ الله
"If you were to ask them who created the heavens and the earth, they would say, 'Allah.'" [Quran, 39:38]
وَلَئِن سَأَلْتَهُم مَّن نَّزَّلَ مِنَ السَّمَاءِ مَاءً فَأَحْيَا بِهِ الْأَرْضَ مِن بَعْدِ مَوْتِهَا لَيَقُولُنَّ الله
"If you were to ask them who sends the water (rain) from the heaven and gives life therewith to the earth after its death, they would say, 'Allah.'" [Quran, 29:63]
قُلْ مَن يَرْزُقُكُم مِّنَ السَّمَاءِ وَالْأَرْضِ أَمَّن يَمْلِكُ السَّمْعَ وَالْأَبْصَارَ وَمَن يُخْرِجُ الْحَيَّ مِنَ الْمَيِّتِ وَيُخْرِجُ الْمَيِّتَ مِنَ الْحَيِّ وَمَن يُدَبِّرُ الْأَمْرَ ۚ فَسَيَقُولُونَ الله
"Say, 'Who provides you with sustenance out of the heaven and the earth? Who holds mastery over your hearing and sight? Who brings forth the living from the dead and the dead from the living? Who governs all affairs of the universe?' They will surely say, 'Allah.'" [Quran, 10:31]
So when the Prophet PBUH comes to them, it is not with a new god. Their paganism is not the paganism of the modern day. They know Allah is their Lord. But they are not Muslims, and we don't consider them to be Muslims. Why? Because they worship idols. Why do they worship idols when they know Allah created them? The Quran tells us — they say:
مَا نَعْبُدُهُمْ إِلَّا لِيُقَرِّبُونَا إِلَى اللَّهِ زُلْفَىٰ
"'We are only worshiping these beings so that they can bring us closer to Allah.'" [Quran, 39:3]
So their ultimate goal is Allah — the idols were only intermediaries.
Allah says:
وَيَعْبُدُونَ مِن دُونِ اللَّهِ مَا لَا يَضُرُّهُمْ وَلَا يَنفَعُهُمْ وَيَقُولُونَ هَٰؤُلَاءِ شُفَعَاؤُنَا عِندَ اللَّهِ
"They worship besides Allah things that do not harm them nor benefit them, and they say: 'These are our intercessors between us and Allah.'" [Quran, 10:18]
"We are too sinful to worship Allah directly, and these idols are holy beings, so we 'go through' them to get to the Holiest of holy that is Allah"—this is their mentality. So notice their shirk (شرك - idolatry/polytheism) was not in rejecting Allah; they firmly believed Allah is their Creator and Sustainer, but they were worshiping other than Allah — so we don't consider them to be Muslims.
This is important to note because in our times, some Muslims fall prey to this *exact* same mentality. They claim Allah is their Lord, but they feel they are too sinful to worship Allah directly, so they invent intercessors/intermediaries. Change al-Lat to pir, Manat to sheikh, al-Uzza to wali, and you get the exact same concept, word for word. They think they have to 'go through' the saint or the Prophet PBUH. "We worship this being, sacrifice to this being, invoke the blessings of this being, because this being has a higher status with Allah, and they will plead our case to Allah"—this is exactly the mentality of the jahili Arabs. They might say, "How dare you compare a pir to al-Lat! How dare you compare my sheikh to al-Lat!" Our response is: "What is al-Lat except a saint?"
Do you know the origin of al-Lat? Al-Lat was a generous man who used to feed the pilgrims a type of soup. "Al-Lat" means "the one who grinds." (Note: Al-Lat is his title, not his name.) He would stand on the road towards Makkah and feed the people on the road. So they called him "al-Lat," the one who grinds the barley for the soup. When he died, they said, "Let us commemorate him. He was a good man"—so they built a monument. And then people came, rubbed their bodies on it, put their hands on it to get blessings, and slowly but surely, it became an idol that they worshiped besides Allah. So what is al-Lat except a saint? (Note: In our religion, we are not supposed to build a monument on a grave *exactly* because of this reason.)
And the most common being who is invoked and worshiped on earth besides Allah is Jesus Christ. Is Jesus a good or evil being? He is a good being. He is one of the greatest of all prophets. You see, the slippery slope doesn't occur with evil people — look at how few people worship shaytan (the Satanists), and yet billions of people worship Jesus Christ, because it is easy to slip with a good man — you put him above his place, you take him to a status above what he deserves. And this is what our religion came to prohibit. You don't worship anybody besides Allah, including the Prophet PBUH. You don't 'go through' anybody to get to Allah. Take the Prophet PBUH as a role model, not as another god or demigod.
So the shirk of the jahili Arabs was a very unique type of shirk, unlike the Hindus or the Zoroastrians — because these groups believe in another god besides Allah; but the god of the Arabs was the God of Ibrahim and Ismail and Ishaq, and that is Allah, the God that we Muslims believe in. Their shirk was not in rejecting Him, but ironically, in affirming Him as being too Holy.