Savannah Guthrie and her family are clinging to faith amid their nightmare … and a message of hope is coming straight from her mother Nancy’s pastor, who is vouching for the power of prayer when tragedy threatens to take over.

Michael Rudzena, the pastor at Good Shepherd New York in Manhattan — who Savannah introduced to her mother a decade ago — sat down with Hoda Kotb on Tuesday … explaining how prayer fights against a sense of fatality and despair that clouds hearts when bad things happen.

Rudzena described 84-year-old Nancy as strong and fiercely loving … saying over the years he came to understand her faith deeply when she streamed his church services from Arizona and attended in person when she was in NYC.

Prayer has become a cornerstone for the family, with Nancy’s other pastor, John Tittle of St. Andrew’s Presbyterian Church in Tucson, offering prayers over the weekend … even praying for the hearts of whoever is responsible for her disappearance.

On Monday, Savannah took to IG, saying she and her family refuse to give up hope that Nancy is alive and are desperately asking the public for help in finding her. The second of two deadlines outlined in an alleged ransom letter expired last night … the note demanded $6 million in bitcoin, which the Guthries said they would pay. It’s unclear so far if they have.