Ernest Hemingway's prose style is often considered straightforward. He avoided what is called "purple prose," giving the reader only as much description as needed and keeping dialogue tight and natural. This style was the result of training as a journalist, in which overt poetic technique is generally shunned in favor of sparse, tight writing.
While such a style would seem antithetical to interesting and absorbing drama, it works in Hemingway's favor. In A Farewell to Arms, the prose style would appear to be at odds with what is often a highly emotional story, but the lack of flowery description or melodramatic dialogue helps sell the realism. It prevents the love story between Frederic and Catherine from sliding into melodrama or sentimentality since everything is presented so plainly to the reader.
Even more emotionally charged moments, such as when Frederic prays for God to save Catherine from dying after she starts to hemorrhage in child-bed, are depicted in this way:
The nurse went into the room and shut the door. I sat outside in the hall. Everything was gone inside of me. I did not think. I could not think. I knew she was going to die and I prayed that she would not. Don't let her die. Oh, God, please don't let her die. I'll do anything for you if you won't let her die. Please, please, please, dear God, don't let her die. Dear God, don't let her die. Please, please, please don't let her die. God please make her not die. I'll do anything you say if you don't let her die. You took the baby but don't let her die. That was all right but don't let her die. Please, please, dear God, don't let her die.
The repetition of phrases like "please" and "I'll do anything" alone sells the desperation of Frederic's prayer. He slightly rephrases the same plea over and over, never becoming too flowery or eloquent in his basic desire for Catherine to survive her post-labor trauma. There is nothing artificial about this peek into Frederic's mind either as it reads quite naturally: after all, few people are poets when praying in an hour of fear, as Frederic is here.