Before Islam, in the period Muslims call the Jahiliyyah (the age of ignorance), idol worship in Arabia took many forms. Whenever a caravan left Makkah, its people would chip a piece of rock off the Ka'bah and take it with them to worship as an idol. In Islam, the bricks of the Ka'bah were never sacred in themselves, since the building has been rebuilt many times. What is sacred is the land of Makkah. One companion recalled that when travelers in the desert could find no rock, they would pile up sand, squeeze goat's milk over it to make it firm, and walk around it in worship (tawaf).
One of the worst stories is that of the idols Na'ila and Isaf. Na'ila stood on the hill of Safa and Isaf on the hill of Marwa. The Quraysh would touch them as they walked back and forth between the two hills in sa'i. The history books say that Na'ila and Isaf had been two lovers who could find nowhere to be alone except inside the Ka'bah, and they were intimate there. As a punishment, Allah turned them to stone on the spot. The Quraysh took this for a miracle and set them up on Safa and Marwa.
When Islam came, the early Muslims felt uneasy about performing sa'i because of these idols. Allah then revealed that Safa and Marwa are among His signs (Qur'an 2:158). This assured them that the hills were holy long before Na'ila and Isaf, and had nothing to do with them.
The Quraysh also believed that the angels were Allah's daughters, and they worshiped the angels for that reason. By the time the Prophet ﷺ conquered Makkah, about 360 idols stood around the Ka'bah. Some had human shapes, some were animals, and many were half human and half animal. Muslims share one set of core beliefs, the Pillars of Faith (Arkan al-Iman). The pagan Arabs had no such shared creed, and different people believed different things about the idols. The one thing they all agreed on was that worshiping idols brought them closer to Allah.
Other events recorded around the same time. Their order within the year is not established; use the storyline above for the sequence.
Before Islam came, we worshiped rocks and stones, and if we found a rock that looked more beautiful than the one we were worshiping, we would throw the old one away and put the new one in its place. And if we were traveling in the desert and we couldn't find a rock, we would gather sand, put it into a pile, bring a goat, squeeze some milk out of it to make the sand firm, and then we do tawaf around that sand.
Since we were children, we were hearing the story of Na'ila and Isaf.
Explaining why the early Muslims felt hesitant about performing sa'i between Safa and Marwa.
إِنَّ ٱلصَّفَا وَٱلْمَرْوَةَ مِن شَعَآئِرِ ٱللَّهِ ۖ فَمَنْ حَجَّ ٱلْبَيْتَ أَوِ ٱعْتَمَرَ فَلَا جُنَاحَ عَلَيْهِ أَن يَطَّوَّفَ بِهِمَا
“Indeed, [the hills of] Safa and Marwa are among the signs of Allah. So whoever performs the Hajj or Umrah, let them walk between [the two hills].”
This ayah affirmed that walking between Safa and Marwa remained a sign of Allah despite pagan-era idols (Isaf and Na'ila) having been placed there, described among this event's paganistic practices.