Today's first reading is the mysterious departure of Elijah in the whirlwind. His ambiguous passing gave rise to the expectation that he would come again before the day of the Lord to set everything right. (Jesus famously explained that "Elijah has indeed come" and he was John the Baptist.)
When Elijah was taken up, his cloak fell to his disciple, Elisha, who was given a twofold portion of Elijah's spirit (and used it right away to divide the Jordan so that he could cross back to the other side). Wielding the rolled-up cloak like a whip over the waters, Elisha said, "Where is the Lord, the God of Elijah?" This has generally struck me as a kind of challenge, tempting God to show himself. But today I heard it as a prophetic statement, given that he was working the prototypical Israelite miracle of parting the waters: Elisha was giving notice that the Lord was acting through him now, on behalf of Israel. Elijah may have left, but God did not abandon his people.
A note about names:
We have become used to the names Elijah and Elisha, which are closer to their Hebrew versions. But Elias and Eliseus are the same two prophets, when their names are rendered from the Latin.