In “lā khayla ʿindaka,” the final -ka is grammatically a second-person singular suffix. In ordinary communication it addresses another person, but here the speaker and the person addressed are one in reality.
Actual referent: The poet or speaker himself.
Figured addressee: A second person extracted conceptually from that self.
Effect: Internal admonition takes the form of counseling a separate interlocutor.
A second-person suffix does not by itself establish tajrīd. Addressing a genuinely different person is ordinary address; treating one's own self as another addressee is this rhetorical form.