Originally Posted by Abu Omar
The ayaat that you cited did not deny the Prophetic miracles, rather it enforces the point that miracles soley come from Allaah (Exalted is He) and that the Prophet (Peace and blessings of Allaah be upon him) did not create these [signs/miracles]. That's why Allaah (Exalted is He) commanded His Messenger to say: "Am I anything but a man, sent as a Messenger?"
to refute the claim of the Quraysh that in order for them to believe the Prophet; he should have the ability to perform miracles whenever he desires. It is also reapplied in the statement where the Prophet says:
The signs are only with Allaah, and I am only a plain warner.
meaning, the signs come only from Allaah and as I am only a plain warner.
There is a passage in the Bible where Eesa ibn Maryam (Peace be upon him) refused to give a miracle to those who requested:
The Pharisees came forward and began to argue with him, seeking from him a sign from heaven to test him.
He sighed from the depth of his spirit and said, "Why does this generation seek a sign? Amen, I say to you, no sign will be given to this generation."
Then he left them, got into the boat again, and went off to the other shore.
This did not stop him from performing miracles but it demonstrated the Prophet's avowment that all Prophets are humans, just like you and they or the nation[s] that they were sent to cannot demand a miracle according to their desires.
Allaah (Exalted is He) says:
We did send messengers before thee, and appointed for them wives and children: and it was never the part of a messenger to bring a sign except as Allaah permitted (or commanded). For each period is a Book (revealed).
Additionally, some of the 'miracles' requested by the Mushrikeen had no connection in establishing the truthfulness of a claim to prophethood while the other requests where inconceivable demands.
To make it clear, they demanded six things in the ayat; three of them were inconceivable whilst the other three had no connection with establishing the truthfulness of a claim to prophethood.
The first inconceivable claim from the Mushrikeen was causing the heaven totfall upon them piecemeal. This would entail the destruction of the Earth and the death of its inhabitants. Obviously, such thing was already prophesised that it would occur at the end of time. Further, if this 'miracle' was granted, it would be incompatible with the survival of mankind and the guidance toward their perfection that wisdom has determined.
The second inconceivable claim from the Mushrikeen is to see Allaah and this is impossible as Allaah cannot be seen with this wordly eyes. It also attributes limitation to Allaah (Exalted is He).
The third inconceivable claim from the Mushrikeen is to bring down a letter from Allaah. Here they attribute human characteristics to Allaah and far exalted is he from what they ascribe to him.
The other three things had no bearing on the truthfulness of the claim to be a prophet. This is because the Mushrikeen demanded that he should cause a spring to gush forth from the earth, or that they own a garden of date-palms and grapes and abundant rivers, or own a house of gold. Obviously these things have no connection with the claim to be a prophet. How many people have them, yet are not prophets. Indeed, some people have all three of them, yet they are not necessarily believers, let alone prophets. So thus since these things have no bearing on the claim of prophethood, and do not prove its veracity, producing them in the context of proving this veracity would be a futile act that any prophet would not perform.
These are simply reasons behind the rejecting of some Signs that where demanded by the Mushrikeen. The main reason is that all miracles come from Allaah (Exalted is He).