Allah, the Exalted, informs about the magicians when they met Musa, that they said to Musa,

{“Either you throiv first..."} meaning, “you go first.”

This means, “you magicians should go first so that we can see what magic you are going to perform and so that the true state of their affair will become obvious to the people.’

In another Ayah it says that when they threw,

Then said: "By the might of Fir'awn, it is we who will certainly win!"

And Allah, the Exalted, says,

They bexoitched the eyes of the people, and struck terror into them, and they displayed a great magic.

Here, He says in this Surah,

They were a large numbered group and each one of them threw a stick and a rope until the valley became full of snakes piled on top of each other.

Concerning Allah’s statement,

This means that he feared for the people that they would be tested and deceived by their magic before he could even have a chance to throw what was in his right hand. Thus, Allah revealed to him at the right moment, to throw what was in his right hand, which was the stick. When he did so, it swallowed what they had made. It became a huge, monstrous creature with legs, a neck, a head and fangs. It went after these ropes and sticks until none of them remained, except that it was devoured and swallowed by this beast. At the same time, the magicians and all of the people were watching with their own eyes, seeing this amazing event in broad daylight. Thus, the miracle was performed and the evidence was clear. The truth prevailed and the magic was proven to be falsehood. This is why Allah said,

So when the magicians saw the event and witnessed it with their own eyes, while they were knowledgeable of the various tricks and methods in the sciences of magic, they knew with conviction that what Musa had done was not magic or illusionary tricks. They recognized that it was the truth without any doubt. They knew that no one had any power to do this except for One Who says for a thing “Be,” and it is. Therefore, when this happened, they fell down into prostration to Allah. They said, “We believe in the Lord of all that exists, the Lord of Musa and Hartin!” This is why Ibn ‘Abbas and Ubayd bin TJmayr both said, “At the beginning of the day they were magicians and at the end of the day they were outstanding witnesses of faith.”

The Number of Magicians

Ibn Abi Hatim recorded that Ibn ‘Abbas said, “The magicians were seventy men who were magicians in the morning, but witnesses of faith by the time evening came.” Ibn Abi Hatim also reported that Al-Awza! said, “When the magicians fell down in prostration, Paradise was raised up before them until they were looking at it.” It is reported from Said bin Jubayr that he said concerning Allah’s statement,

{So the magicians fell dawn prostrate

“They saw their places (in Paradise) made clear before them while they were in their prostration.” Tkrimah and Al-Qasim bin Abi Bizzah both said the same.