If a pebble falls from his hand and he then finds a pebble under his feet, is that sufficient?

Question:
May Allah reward you, Honorable Shaykh. This questioner says: If a pebble falls from his hand and he then finds a pebble under his feet, is this pebble sufficient for the one that fell?

Answer:
If he takes it from the ground and throws it, there is no harm. What is forbidden is taking it from the pit; he must not take it from the pit. As for the pebbles scattered in the valley or on the road, there is no harm.