The magicians challenged Musa, when they said,

(Either you throw (first), or shall we have the (first) throw?) before you. In another Ayah, they said,

(Or we be the first to throw) [20:65]. Musa said to them, you throw first. It was said that the wisdom behind asking them to throw first, is that - Allah knows best - the people might witness the magicians' sorcery first. When the magicians had cast their spell and captured the eyes, the clear and unequivocal truth came, at a time when they all anticipated and waited for it to come, thus making the truth even more impressive to their hearts. This is what happened. Allah said,

(So when they threw, they bewitched the eyes of the people, and struck terror into them,) meaning, they deceived the eyes and made them think that thet trick was real, when it was only an illusion, just as Allah said,

(So Musa conceived fear in himself. We (Allah) said: "Fear not! Surely, you will have the upper hand. And throw that which is in your right hand! It will swallow up that which they have made. That which they have made is only a magician's trick, and the magician will never be successful, to whatever amount (of skill) he may attain") [20:67-69].

Ibn 'Abbas commented that the magicians threw, "Thick ropes and long sticks, and they appeared to be crawling, an illusion that they created with their magic."