How sound is the story of the barren woman for whom Musa (peace be upon him) supplicated, and she bore children after Allah said: "Verily, I have decreed her barren"?

The story mentioned is not found in the books of Sunnah, and it contains the phrase "My mercy preceded My power," which is strange. What is established is that Allah's mercy precedes His wrath, not His power, as stated in the Hadith Qudsi: "When Allah decreed the creation, He wrote a book with Him, [saying]: 'My mercy has overcome My wrath,' or 'My mercy has preceded My wrath.' So, it is with Him, above the Throne."