Last month I posted an observation on Gollum's first appearance as a character in The Two Towers. I noted then that both this passage (4.i.612-613) and the paragraph in The Hobbit (97) where Bilbo spares Gollum out of pity feature a significant shift in the pronouns used to describe Gollum: the shift from "it" to "he" reflects the failure to maintain the pretense that Gollum is a "thing" and not a person. It is only in the moment that Bilbo is unable to see Gollum as an 'it,' as a 'thing,' that he discovers pity.
But there's another passage that also deserves mention in this context. In The Shadow of the Past Gandalf has been explaining to Frodo that Gollum had been captured by Sauron and revealed to him what happened to the Ring and where it was:
'The Shire -- [Sauron] may be seeking for it now, if he has not already found out where it lies. Indeed, Frodo, I fear that he may even think that the long-unnoticed name of Baggins has become important.'
'But this is terrible!' cried Frodo. 'Far worse than the worst that I had imagined from your hints and warnings. O Gandalf, best of friends, what am I to do? For now I am really afraid. What am I to do? What a pity that Bilbo did not stab that vile creature when he had a chance!'
'Pity? It was Pity that stayed his hand. Pity, and Mercy: not to strike without need. And he has been well rewarded, Frodo. Be sure that he took so little hurt from the evil, and escaped in the end, because he began his ownership of the Ring so. With Pity.'
'I am sorry,' said Frodo. 'But I am frightened; and I do not feel any pity for Gollum.'
'You have not seen him,' Gandalf broke in.
'No, and I don't want to,' said Frodo. 'I can't understand you. Do you mean to say that you, and the Elves, have let him live on after all those horrible deeds? Now at any rate he is as bad as an Orc, and just an enemy. He deserves death.'
'Deserves it? I daresay he does. Many that live deserve death. And some that die deserve life. Then do not be too eager to deal out death in judgement. For even the very wise cannot see all ends.'
(FR 1.ii.59, emphasis Tolkien's)
Admittedly, Frodo never calls Gollum 'it' here, but his words -- 'What a pity Bilbo did not stab that vile creature when he had a chance' -- echo the thoughts that ran through Bilbo's mind -- '...while he had any strength left....He must stab the foul thing' (The Hobbit, 97). Frodo of course knows the true story of Bilbo and Gollum, and that Bilbo very nearly did 'strike without need.'1 And that tale is clearly qute present in his mind right now, since he and Gandalf have both brought it up several times already.2 That whole scene in The Hobbit in fact underlies much of their conversation here. It is one of the two main elements that condition Frodo's reaction to what Gandalf is telling him, the other being Frodo's terror of Sauron. Both of these converge in the revelation that Sauron has learned about Bilbo and the Shire from Gollum, which sparks Frodo's harshness here.3
And just as in this passage Frodo recalls the thoughts of Bilbo long ago, so, too, does Frodo remember his conversation with Gandalf later, at another crucial point (TT 4.i.614-615), with Gollum at his feet and his sword at Gollum's throat.4 And seeing Gollum makes all the difference. He pities him, and spares him, just as Bilbo had done.5 And here, too, his thinking echoes Bilbo's because he decides that it is not right to kill Gollum outright, and when he has not yet done them any actual harm.6
So, given this continuum of recollection, it hardly seems likely that Frodo's words to Gandalf in The Shadow of the Past echo the thoughts of Bilbo in The Hobbit only by coincidence. But what is by far most interesting is what Frodo does with his memory here. Not having seen Gollum, he can deny him the humanity that Bilbo saw and pitied. 'That vile creature' is a step backwards from Bilbo's understanding that Gollum was 'miserable, alone, lost.' To Frodo, here and now, Gollum is 'the foul thing' Bilbo at first felt he must stab and blind, no longer 'he,' but 'it.'
1 Frodo's knowledge of the true story was first established explicitly at: FR 1.i.40; see also FR Pr. 12-13.
2 FR 1.ii.48, 54-60. For further discussion of this scene, see here.
3 Just how extreme Frodo's final statement here is may be gauged from his later statement that 'no hobbit has ever killed another on purpose in the Shire' (RK6.viii.1006). His last three words also make an interesting qualification, given that he knows that Gollum murdered Déagol to obtain the Ring. I have to wonder if this is part of the reason Frodo rejects Gandalf's claim that Gollum is a hobbit. The words 'Now at any rate...Orc' must refer to Gollum's new connection with Sauron, whom, Gandalf has implied, sent Gollum out '[o]n some errand of mischief' (FR 1.ii.59)
4 It is worth remembering that Frodo does not lower his sword until he feels pity for Gollum.
5 Given how vividly his conversation comes back to him here, 'relives this conversation' might be a better description than 'remembers.' He does remember it with interesting differences, however. Some parts of the conversation are left out entirely, and in one case he alters and expands something Gandalf said. He changes 'Then do not be too eager to deal out death in judgement' (FR 1.ii.59) to 'Then be not too eager to deal out death in the name of justice, fearing for your own safety' (TT 4.i.615). It's easy to see how where 'fearing for your own safety' comes from, since Frodo was admittedly terrified during the original conversation. But a detailed analysis of what is included, excluded, and changed will have to await another day. Christopher Tolkien believes that the differences in wording between The Shadow of the Past and The Taming of Smeagol were accomplished 'perhaps not intentionally at all points.' See The War of The Ring: The History of Middle-Earth, vol. VIII (2000) 96-97.
6 At TT 4.i.615 Frodo says 'No....If we kill him, we must kill him outright, But we can't do that, not as things are. Poor wretch! He has done us no harm.' Compare this to Bilbo's 'No, not a fair fight. He was invisible now. Gollum had no sword. Gollum had not actually threatened to kill him, or tried to yet' (The Hobbit, 97). In earlier drafts of The Lord of the Rings the echo had been even stronger. Both in The Taming of Smeagol and The Shadow of the Past it was pointed out that killing Gollum would have been 'against the Rules.' Frodo's statement that they cannot kill him 'not as things are' is a survival of this notion of fairness, that it is wrong to kill an unarmed foe who is at your mercy. See HME as cited above n. 5.