A.T. Robertson Commentary Matthew 8:14

"And when Jesus was come into Peter`s house, he saw his wife`s mother lying sick of a fever." — Matthew 8:14 (ASV)

Lying sick of a fever (βιβλημενην κα πυρεσσουσαν). Two participles, bedridden (perfect passive of βαλλω) and burning with fever (present active). How long the fever had had her we have no means of knowing, possibly a sudden and severe attack , as they tell Jesus about her on reaching the house of Peter. We are not told what kind of fever it was. Fever itself was considered a disease. "Fever" is from German feuer (fire) like the Greek πυρ.