1 Samuel 17:40

And he took his staff in his hand
His shepherd's staff, which he used in keeping his father's sheep, and chose rather to appear in the habit of a shepherd than of a soldier:

and chose him five smooth stones out of the brook;
which ran in the valley, which became smooth by lying in the water running over them; and which being smooth were fitter for his purpose, being the more easily cast out of the sling; though De Dieu is of opinion that these were parts or pieces of stones, cleft ones, which were rough and rugged, and which would more easily and firmly be fixed in the forehead of the Philistine:

and put them in a shepherd's bag which he had, even in a scrip;
in which he had been wont to put things he needed for the good of the flock, and was such as travellers put their food in; and this might also be the use of it with shepherds; but, according to the Ethiopic interpreters ^F11, it was that piece of the leather in the midst of the sling, in which the slingers used to put the stones, that they might stick the more firmly:

and his sling [was] in his hand;
which he intended to use in slinging the stone or stones he had in his scrip; and which was an exercise he had been accustomed to in all likelihood, and for which the Benjaminites his neighbours, of the next tribe, were very famous:

and he drew near to the Philistine;
marched towards him, thereby signifying that he accepted his challenge, and would enter the list with him.