There have been many suggestions for what Behemoth could be over the centuries and it depends on how figurative the passage can be read. Since some of the descriptions suggest themselves as somewhat more literal, the most figurative suggestions (demon, concept of strength, pagan god, myth) should not be taken. A real life animal (elephant, hippo, dinosaur), possibly one we have not discovered fossils for (cryptid), seems to be a better reading.

Whatever the behemoth might be, God's point is that it is a powerful creature and beyond humanity's ability to control. Yet, it still depends on God for nourishment and must humble itself before God. Job was made by God like the behemoth so Job, however important he may be in the order of creation, is dependent on God and should humble himself. The Lord has not forsaken Job (or us in our troubles) but will continue to care for us and deliver us from evil.