E.C. Marchant, Commentary on Thucydides Book 1

23. ὅπλων—is a matter of, ‘calls for.’ Kruger compares e.g. Dem. de Cor..190 ἦν ἐκεῖνος ὁ καιρὸς τοῦ γε φροντίζοντος ἀνδρός. The gen. is one of description.

24. ὠφελεῖ—are of avail. The dat. with ὠφελεῖ is not very rare in poetry (see Jebb on Soph. Ant. 560), but ἠπειρώταις here belongs to ἔστι as much as to δι᾽ ἥν, etc., ‘especially in the case of a land power fighting against a naval power.’ Different explanations have been put forward of the meaning: some suppose Archidamus to allude to the necessity of obtaining a fleet (see c. 81. 4), others think that the allusion is to the equipment of large armies to remain in the field; but this is against the general argument of the speech. In θαλασσίους is included the idea of tribute-paying subjects: the Lac. have no fleet and no subject allies bound to pay for one. (This is a succinet restatement of cc. 81. 4, 82. 1. Archidamus rightly sees that success in a war with Athens depends on getting control of the sea. You cannot conquer a sea power on land, cf. c. 121, esp. 4 and 5, and c. 81. 1, 2. The two things needful to give success to the Pel. are δαπάνη and μελετή.)

[3] 28 τῶν ἀποβαινόντων depends on τῆς αἰτίας, the greater share of responsibility for the eonsequences.

ἐπ᾽ ἀμφότερα—i.e. for good or ill (καὶ εὐκλείας καὶ δυσκλείας says the Schol. on ii 11 δόξαν οἰσόμενοι ἐπ᾽ ἀμφότερα).

1. τι αὐτῶν—i.e. τῶν ἀποβαινόντων, let us take some thought of them beforehand.