Five smooth stones. Brookstones smoothed by the running water and destined to be picked up by a youth named David, whose belief in God banished his fear. Besides, he had had practice. He even took his sling along with him during his visit to his brothers in the Israeli Army. So he must have carried it with him everywhere: for constant practice, surely.
When the lion and the bear had come to raid the flock of the lamb, the lad “smote” the beast. He said so in just those words. I do not think he smote it with his fist or his foot.
After he whirled his sling and stoned the beast, it rose against him and he seized its beard and slew it. Perhaps he bashed its head with another rock. More likely, to me, he carried a knife with him for eating, cutting sheep free of brambles and cleaning fish. I would bet it was sharp enough to dispatch a lion whose head was already damaged by a slung stone. I mean, where would you have aimed?
How do you get to Carnegie Hall? Practice, practice. David must have been gifted with wonderful hand/eye coordination by the Lord. His work ethic must have also been strong to allow him to practice with that sling until he was a deadeye with it.
Poor Goliath. In all his pride, he never had a chance . . .