This is one of the scenes in the novel where we see Beatty and Faber having a contest for the metaphorical "soul" of Montag - Faber has just been giving Montag his point of view and then has to listen while Beatty gives him the opposite view. Montag's plea to Faber before he goes in to Beatty and the other firefighters reflects his own fear of being swayed by Beatty's arguments: "Old man... stay with me."
Beatty's presence and needling makes Montag feel guilty, and interestingly, although it is never made overt, the presence of Beatty makes Montag compare himself with Macbeth in his guilt:
For these were the hands that had acted on their own, no part of him, here was where the conscience first manifested itself to snatch books... and now, in the firehouse, these hands seemed gloved with blood.
As Beatty begins his speech and his narration of the "dream" he had of his argument with Montag, he makes a number of highly topical allusions, such as referring to Psalm 23 and sheep going astray but coming back to the fold. The effect of his speech is clearly painful for Montag:
Montag's head whirled sickeningly. He felt beated unmercifully on brow, eyes, nose, lips, chin, on shoulders on upflailing arms. He wanted to yell, "No! Shut up, you're confusing things, stop it!"
Finally, despite Faber's attempts to interject, Montag is described as sitting like "a carved white stone." It is clear that the arguments of Beatty have been powerful, as Faber concedes that Beatty has "had his say" and that he will have his say to Montag later and he will need to decide.
In this part of the novel therefore we can compare Guy Montag to a prize being fought over by Beatty and Faber. This part however represents a "win" by Beatty - his persuasion and rhetoric has worked on Guy, and Faber recognises that he will need to do some work to win Guy back.