Is it true what was said, that righteous people are able to revive the dead, and was it narrated that Sheikh al-Islam Ibn Taymiyyah said this and used as evidence for it its occurrence at the hands of some prophets and righteous people?

Bringing the dead back to life is a miracle for prophets and a special honor (karamah) for some righteous individuals. It can also be a trial and test for some wicked people, such as the Dajjal. The resurrection of the dead occurred with Ibrahim, Musa, Isa, and Muhammad (peace be upon them all). Examples of bringing the dead back to life are mentioned in the Holy Quran, including the story of Ibrahim with the birds, the story of those who fled their homes by the thousands fearing death, and the story of the one who passed by a ruined town.

Shaykh al-Islam Ibn Taymiyyah holds the view that Musa’s signs, such as the staff turning into a serpent, were greater than bringing the dead back to life. He also stated that Allah brought more people back to life through Musa and other prophets of the Children of Israel than through Christ. Bringing the dead back to life can also occur at the hands of the prophets' followers, which indicates the truthfulness of their prophethood. Ibn Taymiyyah also mentioned that the miracles of Prophet Muhammad (peace be upon him) include bringing inanimate objects to life, addressing the poisoned arm, and the stone greeting him, which are more profound than bringing animals back to life.

As for the criterion for righteousness and sainthood, it is steadfastness (istiqamah), not karamah (supernatural occurrences), as supernatural phenomena can be a delusion (istidraj) rather than a karamah. Not every supernatural event that appears at a person's hands is a karamah; some may originate from those who manipulate with resolve or magic, and these are false. Supernatural occurrences can also come from devils, hence their mere occurrence does not indicate that their possessor is a friend of Allah. Rather, the characteristics of Allah's friends are known from the Book and the Sunnah.

Karamah is a supernatural occurrence that happens at the hands of Allah's friends. The condition for it to be a karamah is that its possessor must be steadfast in faith and adherence to the Sharia; otherwise, it is among the satanic states. Karamah may occur to strengthen faith, establish proof, or be a trial.

In summary: Bringing the dead back to life can occur at the hands of non-prophets and even some disbelievers. The criterion for righteousness is steadfastness upon the Book and the Sunnah.