With verbs of emotion the genitive denotes the cause. Such verbs are to wonder at, admire, envy, praise, blame. hate, pity, grieve for, be angry at, take vengeance on, and the like.
ἐθαύμασα τῆς τόλμης τῶν λεγόντων
I wondered at the hardihood of the speakers 12.41, τοῦτον ἀγασθεὶς τῆς πρᾳότητος
admiring him for his mildness C. 2.3.21, ζηλῶ σε τοῦ νοῦ, τῆς δὲ δειλίᾱς στυγῶ I envy thee for thy prudence, I hate thee for thy cowardice El. 1027, σὲ ηὐδαιμόνισα τοῦ τρόπου I thought you happy because of your disposition Cr. 43b, συγχαίρω τῶν γεγενημένων
I share the joy at what has happened 15.15, ἀνέχεσθαι τῶν οἰκείων ἀμελουμένων
to put up with the neglect of my household affairs A. 31b, τὸν ξένον δίκαιον αἰνέσαι προθῡμίᾱς
it is right to praise the stranger for his zeal I. A. 1371, οὔποτ᾽ ἀνδρὶ τῷδε κηρῡκευμάτων μέμψῃ
never wilt thou blame me for my tidings Sept. 651, τοῦ πάθους ᾤκτῑρεν αὐτόν
he pitied him for his misery C. 5.4.32, οὐδ᾽ εἰκὸς χαλεπῶς φέρειν αὐτών
nor is it reasonable to grieve about them 2.62, οὐκέτι ὧν οὗτοι κλέπτουσιν ὀργίζεσθε, ἀλλ᾽ ὧν αὐτοὶ λαμβάνετε χάριν ἴστε you are no longer angry at their thefts, but you are grateful for what you get yourselves 27.11, τῑμωρήσασθαι αὐτοὺς τῆς ἐπιθέσεως
to take revenge on them for their attack A. 7.4.23. Here belongs, by analogy, συγγιγνώσκειν αὐτοῖς χρὴ τῆς ἐπιθῡμίᾱς
it is necessary to forgive them for their desire Eu. 306c (usually συγγιγνώσκειν τὴν ἐπιθῡμίᾱν τινί or τῇ ἐπιθῡμίᾳ τινός).
a. The genitive of cause is partly a true genitive, partly ablatival.