Islam is a "monotheistic" bastardization of the pre-Islamic polytheistic religion followed by the inhabitants of 7th century Arabia. But... its pagan heritage is clearly evident.
Pagan heritage of worship at the Ka’aba
According to the hadith, the Ka'aba in Mecca was a center of idol-worship, with the Ka'aba housing 360 idols:
Narrated 'Abdullah bin Masud: The Prophet entered Mecca and (at that time) there were three hundred-and-sixty idols around the Ka’aba. He started stabbing the idols with a stick he had in his hand and reciting: "Truth (Islam) has come and Falsehood (disbelief) has vanished." (Sahih Bukhari 3:43:658)
Muhammad discarded the 360 idols but retained for Islam, the Ka’aba with its Black Stone, justifying it with the claim that Abraham and Ishmael originally constructed it. However, there is no historical or archaeological evidence for the existence of the Ka’aba beyond a few hundred years before Muhammad's lifetime.
The Qur'an says Abraham built it:
Remember We made the House a place of assembly for men and a place of safety; and take ye the station of Abraham as a place of prayer; and We covenanted with Abraham and Isma'il, that they should sanctify My House for those who compass it round, or use it as a retreat, or bow, or prostrate themselves (therein in prayer). (Qur'an 2:125)
Muhammed says it was built 40 years prior to the Temple at Jerusalem:
Narrated Abu Dhaar: I said, "O Allah's Apostle! Which mosque was built first?" He replied, "Al-Masjid-ul-Haram." I asked, "Which (was built) next?" He replied, "Al-Masjid-ul-Aqs-a (i.e. Jerusalem)." I asked, "What was the period in between them? He replied, forty years. (Sahih Bukhari 4:55:636)
The Temple at Jerusalem was built by Solomon around 958-951 BC. This implies that if Muhammad were to be believed, the Ka’aba must have been built approximately 998-991 BC. But Abraham lived around 2000 BC and both Abraham and Ishmael would have been dead by then.
If Muhammad is correct, then the Qur’an [and therefore Allah] is wrong. But if the Qur’an is correct in stating that Abraham and Ishmael built the Ka’aba, then Muhammad and the hadith is wrong. The Ka’aba has nothing to do with Abraham or Ishmael.
Worship at the Ka’aba and the kissing of the Black Stone are just the first of many practices adopted from 7th century paganism and repackaged within monotheistic Islam.
The pagan gods of pre-Islamic Arabia were worshipped in the form of rectangular stones or rocks. For example, the pagan deity 'Al-Lat', mentioned in Qur'an 53:19, and believed by pre-Islamic pagans to be one of the daughters of Allah, was once venerated as a cubic rock at Ta'if in Saudi Arabia. An edifice was built over the rock to mark it apart as a house of worship. From the Kitab Al-Asnam (Book of idols):
Al-lat stood in al-Ta'if, and was more recent than Manah. She was a cubic rock beside which a certain Jew used to prepare his barley porridge (sawiq). Her custody was in the hands of the banu-'Attab ibn-Malik of the Thayif, who had built an edifice over her. [...]She is the idol which God mentioned when He said, "Have you seen Al-lat and al-'Uzza (Surah 53:19)?
"A principal sacred object in Arabian religion was the stone, either a rock outcropping or a large boulder, often a rectangular or irregular black basaltic stone… of numerous baetyls, the best known is the Black-stone of the Ka’aba at Mecca which became the central shrine object in Islam"
There is no denying that the Black Stone was one among many stones and idols venerated at the Ka’aba by the pre-Islamic pagans. The Black Stone was kissed during pre-Islamic pagan worship. Though Muhammad threw out 360 other objects at the Ka’aba, he retained this Black Stone and continued the practice of kissing it. It is this same stone that the pre-Islamic pagans once kissed, that Muslims kiss today when visiting Mecca.
Pagan past of Islamic praying and fasting
Pagans prior to Islam would pray five times per day towards Mecca. Muhammad retained for Islam, this pre-Islamic practice, sanctioning it with a story of a night trip to heaven on a mythical beast called al-Buraq. In heaven, the Hadith tells us that Allah demanded 50 prayers per day per Muslim. Upon advice from "Moses", Muhammed bargains with Allah and successfully reduces it to five prayers per day.
Muhammad's pagan tribe, the Quraish, fasted on the 10th of Muharram. Though optional, Muhammad retained this pagan practice too. Here is proof from the Hadith:
Narrated 'Aisha: 'Ashura' (i.e. the tenth of Muharram) was a day on which the tribe of Quraish used to fast in the pre-lslamic period of ignorance. The Prophet also used to fast on this day. So when he migrated to Medina, he fasted on it and ordered (the Muslims) to fast on it. When the fasting of Ramadan was enjoined, it became optional for the people to fast or not to fast on the day of Ashura.
Sahih Bukhari 5:58:172
Doing Tawaf between Safa and Marwa is an Islamic ritual associated with the pilgrimage to Mecca. Safa and Marwa are two mounts, located at Mecca. This ritual entails Muslims walking frantically between the two mounts, seven times. This was originally a pagan pre-Islamic practice. Muhammad retained it for Islam, sanctioning it with yet another Qur'anic revelation. Here is proof from the Hadith about the pagan past of the ceremonies at Safa and Marwah:
Narrated 'Asim: I asked Anas bin Malik: "Did you use to dislike to perform Tawaf between Safa and Marwa?" He said, "Yes, as it was of the ceremonies of the days of the Pre-lslamic period of ignorance, till Allah revealed: 'Verily! (The two mountains) As-Safa and Al-Marwa are among the symbols of Allah. It is therefore no sin for him who performs the pilgrimage to the Ka'ba, or performs 'Umra, to perform Tawaf between them.' " (2.158)
Sahih Bukhari 2:26:710
A myth was also created about Hagar running between these two mounts in search of water until she found the Zamzam Well. Even if this story were true, why is this reason for people to run up and down between two mounts to please a god?
Pagan requirement of “Ihram”
'Ihram' is a state a Muslim enters into for his pilgrimage to Mecca. It involves a series of procedures like ritual washing, wearing 'Ihram garments', etc. Ihram was originally a pagan requirement for worshiping idols during pre-Islamic times. Muhammad retained this practice for Islam. Muslims assume Ihram to perform the Hajj or Umrah. Here is proof from the Hadith regarding its pagan heritage:
Narrated 'Urwa: I asked 'Aisha : ...But in fact, this divine inspiration was revealed concerning the Ansar who used to assume “Ihram” for worshipping an idol called “Manat” which they used to worship at a place called Al-Mushallal before they embraced Islam, and whoever assumed Ihram (for the idol), would consider it not right to perform Tawaf between Safa and Marwa.
Sahih Bukhari 2:26:706
Pagan heritage of Circumambulation
Circumambulation is to go in circles around a particular object. In Islam, worshipers and pilgrims do this around the Ka'aba at Mecca. Pre-Islamic pagans used do it to please the moon god Hubal, the 360 deities and Allah (who was merely one among the many deities worshiped there). Muhammad himself used to do it, even before the 360 idols inside the Ka'aba were removed.
Judaism and Christianity (the religions of those who are considered People of the Book) do not practice ritual circumambulation to please God. Two other faiths which do are Hinduism and Buddhism, religions older than Islam and accused by Islam of “paganism” and practicing idolatry.
Pagan heritage of Islamic Crescent Moon
Hubal was the moon god worshiped at the Ka’aba. The crescent moon was Hubal’s symbol. Muhammad's pagan grandfather Abd al-Muttalib almost slaughtered Muhammad's father Abdallah at the Ka’aba, to satisfy his god Hubal. From Ibn Hisham:
An arrow showed that it was 'Abdullah to be sacrificed. 'Abdul-Muttalib then took the boy to Al-Ka'bah with a razor to slaughter the boy. Quraish, his uncles from Makhzum tribe and his brother Abu Talib, however, tried to dissuade him. They suggested that he summon a she-diviner. She ordered that the divination arrows should be drawn with respect to 'Abdullah as well as ten camels. … the number of the camels (finally) amounted to one hundred. … They were all slaughtered to the satisfaction of Hubal.
The Ka’aba, Islam's holiest shrine, has been a place where such pagan human sacrifices and slaughters have taken place for Hubal and rivers of blood have flown. When Muhammad founded Islam, he threw out Hubal. At the Battle of Badr, his enemy Abu Sufyan praised the high position of moon god Hubal, saying "O Hubal, be high". Muhammad asked his followers to yell back, "Allah is higher".
Is moon-god Hubal no longer "higher"? Is Islam completely free of the 'moon' influence? Take a closer look at mosques all over the world, and you are likely to find Hubal’s symbol, the crescent moon, positioned at a high point of the mosque. As with the Cross for Christianity and the Star of David for Judaism, the Crescent moon is today a universal symbol for Islam.
It may not be a deliberate effort to worship Hubal. And yet, interestingly, through Islam, the pagan prayer of Muhammad's enemy Abu Sufyan at Badr has been answered, "O Hubal be high". With such rich pagan heritage, let not Muslims claim that theirs is a pure religion that descended directly from Allah’s heaven.