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 niccaj buddhagata sati (whose mindfulness is day and night constantly directed to the Buddha). The subject is the noun sati (mindfulness, nominative singular). It has an attribute, the compound buddhagata (directed to the Buddha, nominative 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.
In the city of Rajagaha there lived a woodcutter. One day he took he and his son went to the forest to cut some wood. On the way back they stopped by a cemetery and ate their meal. While they were eating, their two oxen wandered away from them. When they realized this, the father went to search for the oxen and told the son to stay with the cart. The father found the oxen on the city but by that time the city gates were closed and he could not leave the city. The boy stayed outside by himself. He crawled under the cart and slept. At night, two spirits came and tried to frighten him. The boy cried, "I pay homage to the Buddha". The spirits immediately felt they had to protect the boy. One of them went to the palace of King Bimbisara and brought the king's food tray full of food. The boy ate and then slept until morning. The spirits left a message for the king written on the food tray (but only the king could read it). In the morning the king's servants started to look for the tray. Finally they found it with the boy. They thought he stole it therefore they took him to the king. The king found the note on the tray and realized that this case was not easy. The boy kept telling them his parents came to him in the sleep and fed him. The king then sent for his parents who said they slept at home. The king decided and took all of them to see the Buddha. The Buddha explained what happened. The king then asked if mindfulness directed to the Buddha is the only way to guard against danger. The Buddha further explained by six verses (this one and the following five, DhP 297 - DhP 301) that mindfulness in general is the way to guard against danger.