Plutarch, De Tranquilitate 475a
“The poet illustrates well how powerful the unexpected can be. For Odysseus wept when his dog was fawning on him, but he showed no emotion at all when he sat next to his weeping wife. In the second scene, he arrived with his emotions in hand and managed by reason, but in the earlier he encountered something surprising, all of a sudden, without expecting it.”
εὖ δὲ καὶ ὁ ποιητὴς οἷόν ἐστι τὸ παρὰ προσδοκίαν ἐδίδαξεν· ὁ γὰρ ᾿Οδυσσεὺς τοῦ μὲν κυνὸς σαίνοντος ἐξεδάκρυσε (ρ 302. 304), τῇ δὲ γυναικὶ κλαιούσῃ παρακαθήμενος οὐδὲν ἔπαθε τοιοῦτον (τ 211)· ἐνταῦθα μὲν γὰρ ἀφῖκτο τῷ λογισμῷ τὸ πάθος ὑποχείριον ἔχων καὶ προκατειλημμένον, εἰς δ’ ἐκεῖνον μὴ προσδοκήσας ἀλλ’ ἐξαίφνης *** διὰ τὸ παράδοξον ἐνέπεσε.
Here’s the moment in question: Hom. Odyssey 17.300-305
“There lay the dog, Argos, covered with pests.
But then, where he recognized that Odysseus was coming near,
He wagged his tail and flattened both ears,
But he could no longer rise to meet his master.
Then Odysseus looked sideways and wiped away a tear,
Easily escaping Eumaios’ notice; then he questioned him.”
ἔνθα κύων κεῖτ’ ῎Αργος ἐνίπλειος κυνοραιστέων.
δὴ τότε γ’, ὡς ἐνόησεν ᾿Οδυσσέα ἐγγὺς ἐόντα,
οὐρῇ μέν ῥ’ ὅ γ’ ἔσηνε καὶ οὔατα κάββαλεν ἄμφω,
ἄσσον δ’ οὐκέτ’ ἔπειτα δυνήσατο οἷο ἄνακτος
ἐλθέμεν· αὐτὰρ ὁ νόσφιν ἰδὼν ἀπομόρξατο δάκρυ,
ῥεῖα λαθὼν Εὔμαιον, ἄφαρ δ’ ἐρεείνετο μύθῳ·
Go here for the full scene (the tale of Argos’ youth and his sudden death…)