Idolatry in Jahiliyyah-era Arabia took many forms. Whenever a caravan left Makkah, its people would chip away a piece of rock from the Ka'bah and take it along as a portable idol to worship, though as Muslims recognize, it was never the bricks of the Ka'bah itself that were sacred (the building has been rebuilt many times over the centuries), only the land and location of Makkah. When traveling in open desert with no rock available, some would gather a pile of sand, firm it with a squeeze of goat's milk, and perform tawaf around that instead.
One of the most notorious stories was that of the idols Na'ila and Isaf, placed respectively on Safa and Marwa. The Quraysh would touch them while going back and forth in sa'i. The books of history relate that Na'ila and Isaf had originally been two lovers who, finding nowhere else to be alone together, consummated their relationship inside the Ka'bah itself, and Allah petrified them on the spot as a punishment. The Quraysh mistook their fate for a miracle and placed their likenesses on Safa and Marwa. When Islam came, the early Muslims felt uneasy performing sa'i because of this association, so Allah revealed that Safa and Marwa are among His signs, a reassurance that the two hills' sanctity had nothing to do with Na'ila and Isaf, who came long after.
The Quraysh also held that Allah had daughters who were His angels, and worshiped the angels on that basis. By the time the Prophet ﷺ conquered Makkah, around 360 idols of every shape and size (full human figures, animals, and half-human half-animal forms) stood around the Ka'bah. And unlike the Muslims' unified Arkan al-Iman, the pagan Arabs held no single creed: different people believed different things about the idols, agreeing only that idol-worship was somehow a means of drawing 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.