And the explanation that breaking stones to make pebbles is an innovation, because the one who breaks stones considering it a Sunnah causes hardship to people and tires himself.

Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrates that the Messenger of Allah (peace and blessings be upon him) ordered me on the morning of Aqabah (10th of Dhul-Hijjah): "Come, pick up pebbles for me, small ones (which can be thrown between two fingers)." When I placed them in his blessed hand, he said: "Take pebbles of this kind, just pick such pebbles. Beware, avoid exaggeration in religious matters, for those before you were destroyed because of exaggeration in religion."