miracle

Can you please tell us about the Islamic sources (Quran, Hadith) from which it becomes clear that the miracles the Dajjal (Antichrist) will perform (like ordering the skies to rain and then it will rain) are only because Allah SWT will permit them to happen, i.e. the miracles of the Dajjal (like ordering the skies and rain and then it will rain) are only because of the Will and Power of Allah SWT.

I'd like to know the position of Islam concerning the Christian saints and the miracles that Christians say they perform. Is it allowed that a man or a woman, obviously with the permission of God, could perform such miracles? How can a human being have some miraculous powers (including clairvoyance) if everything comes from God and from Him only? Do we consider those men and women only like wizards or mere deceivers?