Othello's use of metaphors comparing Desdemona's skin, or outward appearance and reputation, to snow and smooth alabaster communicates his original view of her, prior to being made to believe she had betrayed him and slept with Cassio. .
This pure image of Desdemona that Othello expresses quickly changes to reveal his new rage against her: "Yet she must die, else she'll betray more men" (5.2.6). Here Othello is still struggling with making the right decision and is trying to justify killing along with his jealousy by reasoning with himself that he is only doing this for the good of other men so they won't eventually be betrayed by her also. Othello continues reasoning with himself to go ahead and kill Desdemona: "Put out the light, and then put out the light" (5.2.7). This line means more than one thing. Primarily, Othello is planning to "put out the light" of his lamp and then "put out the light" of Desdemona's life. A secondary meaning also shows Othello trying to reason for himself and justify his anger because the word "light" has a connotation that goes with love and happiness in one's life. Therefore Othello is telling himself that since Desdemona's actions have ruined and "put out the light" in his relationship and life that he is now justified in going through with the murder.
At this point in Othello's speech, we continue to see his conflict about what to do as well as how he views himself and his own power: "If I quench thee, thou flaming minister, I can again thy former light restore Should I repent me" (5.2.8-10). On the surface, Othello is continuing to compare Desdemona's life to the light of his torch and reasoning that if he were to put out the light of his torch, he would be able to relight it, even if he changes his mind about killing Desdemona. Another meaning within these lines is showing Othello's struggle with the power within himself.
