The original post: why God doesn't heal the amputated
God created the World: this life in the material World a temporary one: and made the Next Life a permanent life.
The life in the World is short and very short in comparison to the Next Life. In the life of the World man may suffer evil, distress, disease, poverty, accidents ...etc.
If man has any defect in this material life, he will be intact in the Next ethereal life.
Quran 21: 35
{35. Every soul shall taste [of the pain] of death; and We try you [once] with evil and [another time with] good, so as to check you c, then to Us you shall be returned [following your death d.]
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c To see will you be patient in distress, and be grateful in the prosperity, or will you blaspheme and be ungrateful?
d And We will then reward you according to your work: the grateful for his gratitude, and the ungrateful for his non gratitude and blasphemy.
Moreover, who said God does not answer the prayer; God answers the prayer, but most people do not show gratitude.
The religion in its essence is the prayer from God and asking and supplicating Him, and He answers the prayer, I cannot deny that God answered and still answering much many of my requests and prayers, although not all of my praying and asking and supplicating: it could be delayed to another time if He pleases.
The answering of prayer is not a must that God is obliged to give; no it is as He likes and as He wills; we only supplicates Him in every situation.
So man may ask God whatever he wants, and there are conditions to make such answer more probable and more near to be answered.
This is a translation of a prayer which I do respect:
((God! You Who gives to the one who asks of You;
You give to the one who have not asked of you; You give to the one who does not ask of You and who does not know You; so give me according to my prayer from You all the blessings of the life of the World and the Next Life; it is not decreased whatever You give out of Your generosity and kindness. And praise and thanks be to God the Lord of nations.))
And all of you; you asked of Him, and He gave to you, and you deny.
He gives to you, and you are ungrateful and deny His grace and His kindness, and if you are in distress, danger and necessity, then you will know your Lord.