Is the speaker in Surat Al-Kahf, verses 39-42, the believing man or his companion?

The verses speak of a parable of two men, one a believer and the other an unbeliever. The believer in God spends in His way and hopes for His reward, while the unbeliever denies and does not believe in the unseen. The story begins by describing two gardens belonging to one of the men, then he says to his companion: "I am more than you in wealth and mightier in [respect of] retainers." The believing man replies: "Have you disbelieved in He who created you from dust and then from a sperm-drop and then proportioned you [as] a man?" The context concludes with the destruction of the two gardens and their owner's regret, which is a lesson and admonition for Muslims. Sayyid Qutb believes that the story represents fleeting and enduring values; the first forgets the Bestower, while the second remembers his Lord.