Hicks: He will be armed against fortune

Yonge: he will resist fortune,

Mensch's seems to translate this as: "he will face his destiny" which seems more Stoic than Epicurean.

Original text: τύχῃ τ᾽ ἀντιτάξεσθαι,

There no negation in the original (other than the prefix ἀ), so this characteristic is fully governed by the verb.

• ἀντιτάξεσθαι = will be set opposite to (necessity), will range in battle against (fate)

• τύχῃ (dative case) = (by/for) necessity, (by) fate

Suggested option for translation: He will oppose fate.