Anne Graham Lotz, 70, revealed the news on her website this week in a post entitled "My Cancer: Fuel for the Fire".
She said that she received the news of her diagnosis on 17th August between 3:00pm and 3:30pm, which was three years to the day and at the same time she found her husband unresponsive in their pool. He died two days later.
"When I realised the strange 'coincidence' of the timing, I came to the chilling conclusion that it was an assignment from the enemy," she said.
"But just as that thought was forming, I heard the soft, gentle whisper of the Spirit, reminding me that it was on a Friday, during that very same time...between 3:00 and 3:30 in the afternoon...that God's Passover Lamb was sacrificed.
"Jesus died on the very same day of the week, at the very same time of the day, crushing the head of the serpent, forever defeating the devil and death."
Lotz said she will worship and trust God "who is ultimately in control of everything".
She has asked for prayers ahead of her surgery scheduled for 18th September.
"Pray for God to heal me in whichever way He deems would bring Him the most glory," she added.
Lotz's father, Rev Billy Graham, died at the age of 99 in February.
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