The subject is the compound gotamasavaka (disciples of Gotama, nominative plural). The verb is pabujjhanti (awaken, 3rd person, plural, active indicative, present tense). It has two attributes, the adverbs suppabuddhaj (well "awakenedly") and sada (always). There is a clause dependent on the subject: yesaj diva ca ratto ca bhavanaya rato mano (whose mind is day and night devoted to meditation). The subject is the noun mano (mind, nominative singular). It has an attribute, the past participle rato (devoted, nominative singular) with its attribute, the noun bhavanaya (to meditation, dative singular). The verb is omitted, implying the verb "to be". It has three attributes, the adverbs niccaj (constantly), diva (by day) and ratto (by night). The last two of these are connected by two conjunctions ca (and). The relative adverb yesaj (whose, genitive plural) connects the clause to the subject of the main sentence.
The story for this verse is identical with the one for the previous verses (DhP 296 - DhP 300). The forms of meditation described in the previous five verses are the most important in Buddhist practice. By following all of them, by devoting our minds to meditation day and night, we can truly hope to achieve the Awakenment and be free from suffering.