What two things are being compared in the sentence. Swords of rain stabbed the earth

rain and swords

Explanation:

This sentence compares swords and rain. Swords are a weapon made of metal that are very sharp and were used in the Middle Ages as the principal fighting tool. Being stabbed by a sword was often mortal as they were kept very sharp.

Rain is a form of precipitation in the form of liquid that is produced by rainclouds. Therefore, the idea of rain being like swords means that the rain was falling fast and heavy and probably stung the skin as it made contact.