Throwing the pebbles is an expression of the pilgrim’s intention to obey Allah’s commandment, and a demonstration of his humility and servitude to Him. It signifies compliance with the divine commandment without any trace therein of any selfish pleasure; sensuous or intellectual. Sheikh Sayyed Sabiq states in his well-known book Fiqh Us-Sunnah: “Ibn `Umar used to pick his pebbles from Muzdalifah, and so did Sa`id ibn Jubair. Ash-Shafi`i regards this preferable, but according to Ahmad one may pick pebbles from anywhere one wants.
`Ata’ and Ibn Al-Mundhir hold a similar view, for in the hadith of Ibn `Abbas, the Prophet told him, “Come, pick some pebbles for me!” The words used by the Prophet (peace and blessings be upon him) are “pick (some pebbles) for me” without specifying the place whence these were to be picked.
According to the Hanafi and Shafi`i schools and Ahmad, it is permissible, though undesirable, to use pebbles that have been used before. Ibn Hazm holds it permissible without any dislike. He says, “Throwing the pebbles that are used before is permissible, and so is throwing pebbles while mounting an animal.”
Neither the Qur’an nor the Sunnah forbids the use of used pebbles. Logically speaking, had those pebbles not been re-used by multiple pilgrims, there could have been mountains of them in the area. As to throwing pebbles while riding one’s mount, we read in the hadith of Qudamah ibn `Abdullah that he said, “On the Day of Sacrifice, I saw the Prophet (peace and blessings be upon him) throwing pebbles on the first Jamarat Al-`Aqabah while he was riding a light-colored she-camel without throwing them hard or slow, nor pushing and shoving others.